Permanent estrangement from young grandson

This is long and complicated but I'll try to shorten it.
My son is a covert narcissist, very evil. My therapists and psychiatrist agree so it isn't just me. I researched extensively and I do have an education in psychology.
Back in 2021, when my grandson was born, he and the mom were living with mom's parents. She had severe pp depression, yet my son was virtually no help, never waking til after 1 pm, refusing to change poopy diapers, refusing to help or be sympathetic to the mom, it's always about his mental health. Eventually, the mom couldn't take it any more so kicked my son out when baby 6 months. Son stayed with brother and his fiance for 6 weeks, driving them crazy as he's a slob and their wedding was in a month. They had no room or time for my son to see my grandson every weekend, so I'd drive 2 hours each way Saturday to bring them to my home, and another 4 hours Sunday. After 6 weeks, the mom let him move back in because he was trying for half time custody, which she knew he was incapable of, and she couldn't fathom not seeing the little guy so much. My son was full of false promises, so nothing changed. He is a gamer so needed minimum 2 hours uninterrupted daily, and 2 hours for watching his tv shows uninterrupted. After he turned down a much better paying day job, because he wouldn't have enough alone time, and actually expected gps to watch baby after work, so my son could have alone time. He told the mom that if he knew parents wouldn't fill in, even when he was home, he never would have had a baby. Mom had had enough, and I let my son move in with me, and I drove the 8 hours every weekend to pick up my gs. I did 90% of care, including taking him to emergency during severe anaphylactic shock, while my son chose to sleep and even unplugged phone. He never once woke up before 1 pm, even when not working at all. I became very close with the mom, sharing our similar issues. My gs had horrible, untreated eczema,which caused much stress. My son controlled everything in my house, but refused to help with chores or ever get up with gs, even though with my insomnia and winter depression, it was very hard on me, but I loved all the time with my gs. After a year, I'd become very close with the mom, and she assured me I could see my gs lots if I kicked out my son, which I finally did, giving him a month's notice. As soon as he moved out, he called children’s Aid on me, saying I was mentally unstable to watch my grandson, ironic and easily proven as a lie, as I'd been main caregiver for a year. It wasn't unexpected as he'd constantly threaten, when he lived with me, that if I ever asked him to leave, there would be consequences ( taking away my grandson). There was at the time, no legal agreement at all re custody, visitation child support. As the mom was obviously the competent parent, and we had become very close, having shared same difficulties with my son, I helped her hire a lawyer to get legal agreement.
Very tragically, the mom, my only and closest friend passed away suddenly September 2025, a year ago, and my son got custody. I was and am destroyed, especially since I was unwelcome by her family. She'd had a lot of issues with her parents for years, them refusing to follow her boundaries with the baby, and them berating her for kicking my son out, as she hid the truth about my son from her parents. The parents blamed me for convincing her to stand up to them. In truth, we both helped each other with our very difficult families. She invited me to stay with them at least several days a month, and allowed me frequent visits with my gs at my house. We 3 were all very close.
A week after she died, my son informed me I could only see my gs 3x a year, Halloween (that was our very special time that I'd always participate in with his mom and him, xmas, and summer. We had one visit in October to celebrate Halloween, a fun but difficult time as him mom had just died. I asked about xmas visit and was told no, no reason given. I asked in march when I could see my grandson, and was told that my son had found out something, and I needed to grovel and beg for forgiveness, without saying what it was. I rightly assumed he found out about how I'd helped the mom pay for lawyer. If I thought for one minute, giving him equal money, would fix it all, I would have. But, my 2 other sons who know how evil and narcissistic he is, as well as my therapist and Dr., agreed his control and manipulative behaviour would never stop. The game playing of withdrawing visits and doing everything to hurt me, would be detrimental to my gs and me. He also refused to give me his address, so sending cards, pics or letters was impossible. My son's wife, who Id never met, hated me and encouraged my son to cut me off.
I've since received 2 letters from son, saying how evil I am, saying if I begged and apologized for helping the mom, not him, he'd open the door a crack. I'm opposite of my son, and many people as I am unable to lie. I have zero regrets for helping the mom get a custody agreement as she was an amazing, loving, mom, who truly valued me as a grandma and a true best friend, who accepted me 100%, unlike my own family. I'm a very unusual person who speaks the truth, is unable to wear a mask to fit in, dresses like a hippy, and enjoys deep conversations, as I spend a lot of time learning about the world, politics, etc, not frivolous chit chat. I have always had to walk on eggshells around my family, as they don't understand me, and are afraid I'll say the wrong thing.
My estranged son, recently sent another letter, saying how evil I am, and he hopes I live a very long painful life!! Not once has he ever thought or mentioned the damage he's done to his son, who lost his mom and grandma forever, within a month. It's always just about him.
I'm so broken, I have zero desire to live. My 2 sons that still like me, now refuse to see me because I'm apparently too depressing. None of my family has been there during my grief, as they don't understand my overwhelming grief at losing 2 very important people to me. They had been unreasonably jealous of my relationship with the mom and my grandson, for the last couple years, even though I was always there for any of them or my other gks. They, like many, don't understand grief, and I've always been a very emotional, highly empathetic person who gives everything ( as I've always been afraid of rejection since childhood), but recently realized it's only one way. They never even ask how I am, despite knowing I'm at the end of my rope. Their father is a narcissistic and compulsive liar who caused me a lot of pain when we split up, due to his abusive and controlling behaviour.
So, its been almost a year, I'm more depressed than ever, have just 1 friend who because of her difficult childhood, and mental health issues, can't be much support. I no longer trust people, and as I live in a very conservative, religious area, I just don't fit in, being a open atheist,despite 10 years trying to find people who share my interests.
I almost died of an anaphalatic shock a month ago, and since then, I've been totally focused on gathering pics and videos and a letter explaining that my disappearance was definitely not my choice. My one dil is my executor and will make sure when my gs is of legal age, and no longer under his dad's roof, my gs will get the box of things I have been preparing for him. The info about why his father cut me off is in a clearly marked envelope, warning him to only open when ready for the truth. Knowing his father, I have zero doubt there relationship will eventually turn bad, as my son has shown for years, he only really cares about himself.
Anyway, whether anyone reads this or understands my pain, I don't hold much hope. I've never encountered anyone who has a situation like this, so complicated, no hope of ever seeing my grandson again, worrying about him daily, and grieving his mom at the same time. My son has lied to everyone about the truth, faking pain at the mom's death to turn my oldest son totally against me too.
I have zero to live for, I tried very hard to find a new life, but I rarely get more than 1 day in a row, that isn't dominated by grief, so hard to make plans. I'm just trying to prepare for my death and hope I find a wasp before winter comes, so my pain will end. It was 1 wasp sting that nearly killed me last month. I cannot live this way anymore, Ive had a very fulfilling, adventurous life, and am ready for the end. My kids will be free of having me as a burden, and will all benefit from my estate.