Estrangement/Grandpa rent Alienation

My nightmare with my ES does not seem to end. He has always been a difficult son but now it is worse since my DIL came into his life three years ago. They have a son who is 9months old and use him as a pawn to hurt me . For the 1st three months they let me have full access to him. Now they keep him away as I have decided to sell my house where they have been staying without paying any bills at all. I had to come to this difficult decision as my son has been very manipulative since his Dad died of cancer 6 years ago. I wake up everyday feeling horrible and helpless. He will only leave the house if I give him 200 to 300 hundred thousand as he claims that housing is very expensive. My son and DIL have made my life so miserable that I don't fee like waking up in the morning. I loved my grandson so much but I hear him in my house but cannot go near him as my DIL claims that I have depression. I have never felt so helpless and terrible as I feel now. Sometimes I wish I had died instead of my son. This feeling is just drowning me.