Hi Val05
I am so sorry that this is happening to you and your family. I had to reply because your story was so similar to my own.
My son too changed his whole character whilst smoking cannabis. He went from a loving, caring and unassuming chap to someone who was unrecognisable. Anger was a big issue where it really didn't exist before.
I can sit here and type an essay, no a book, on the incidents and events that happened during this time. It eventually took a toll on my own mental health as I felt, as I suspect that you are feeling right now, very helpless.
The things that we did that were positive (and believe me, there were a lot of things we did that turned out to me negative). Firstly, we found him accommodation in a Christian run lodge. They were able to give my son, when he was ready to, help with his addiction(s). He would listen to them when he wouldn't listen to "Mum and Dad" even if it was the same advice. It helped. It also meant that him leaving home was much more controlled that just throwing him out. I also knew he was safe.
Secondly, my husband and myself attended a group for people who had an addict in their lives. I understand the embarrassment you may have in telling friends and family but this group are set up so that you can express your feelings. We found it very supportive.
Thirdly, when my son had moved out, we met him on neutral ground. So we were always in contact, even though a great many of well-meaning friends told us to just "cut him off". Like you, I never could. I still loved my son no matter what. If you meet on neutral ground, there is less opportunity for raised voices/anger etc. Also, in my son's case, when he was at home, he would use the opportunity to steal what he could to fund his habit. I found that never giving him money too was to best thing. I was happy to order him a supermarket shop but money would only ever be spent on one thing.
Long story short, over many years, we had times when he appeared to be cured on his addiction but would always return BUT he did do it in the end. For the last 5 years, my son has returned to his old self. Now his only addiction is gardening. He is getting married soon and now, my relationship with him is very normal. For a long time, I was extremely careful in what I said to him and felt as though I was tip-toeing around him but now it's just like a normal Mum/son relationship. Sure we have our ups and downs but by and large it's really good.
So, I understand this place you are in at the moment Val05. I wish you weren't there but there is help and support and most of all hope.
I wish you well. Take care.