My heart goes out to you, ADD. We do the best we can. You said you shouted at them and were hard on them. Made them do wt things. You didn't beat them mercilessly, spit on them, make them sleep in cages. You said you are sorry multiple times. How many times do you have to say it? You are going to a therapist to become the person HE wants you to become. Is he also going to therapy to work on his anger issues? He needs to. How is your relationship with your other son?
My husbands father was a drunk for some of the time my husband was growing up. He was abusive physically during that time. He didn't really support the family very well, even tho he had a good job, they lived in a bad area with my hubby's invaliid granny in her house.When he got drunk, he would trash the house, and they would all sit outside waiting for him to pass out. When he quit drinking, they stayed in bad areas because he refused to spend his money to live in a decent area. They went to poor schools. He made good money, he was UAW. But anything they wanted they had to earn their own money for it. My husband actually shined shoes as a kid downtown. Father in laws money was his, and he kept in in the bank. My mother in law worked a minimum wage job she had to walk to, and he gave her a couple small utility bills to pay. In his later years,(they had to move in their 60's, cause they could hear gunfire at night, and we all refused to visit them any more) he had a stroke, and all 3 sons took turns going to the house to help take care of him so he didn't have to go into a nursing home. That is called Christian love.
Your son obviously considers himself a Christian. Isn't he supposed to forgive? Isn't that what Jesus instructed us to do? Didn't he die so we could be forgiven? You can't take back the past. You have tried to make amends. He is being a very poor Christian example to any children he may have. What if they decide they don't want to talk to him later on because they feel he should have done things differently? Do you think his wife and/or her family may be fueling this? Her job as a good Christian. wife should be to try and heal things.
It is time for you and your poor dear wife to move forward and live the best lives you can. Perhaps it is time to turn the tables and tell him again you love him and his family, your sorry for the past you cannot change, but this discussion is over. Call you when he's ready to move forward. And continue therapy because it is what YOU want, not because he demands it. And he really does need it as well to work through his anger. There has to be some deeper cause for his behavior. Much love to you and your wife.