AITA for kicking my son out

Hi reddit I know its late but this is something I need to know. I have three children James(23M), Tina(18F) and Gabriel(15M)

When James was 14 we fostered Tina and Gabriel. We went through all the right steps, we asked our son if he was okay, asked our family if they would be willing to accepts them as one of our own. We started therapy for them and us as a family. We made sure our son was still loved. For the first few years things were great and everyone was happy. However towards the end of the fourth year things began to sour. Out of no where our son was becoming rude and impatient with his siblings. We asked him if something was wrong and if he needed to talk to us. He told us he was fine. He got into a really good college which my parents are paying and left. During his third year break is when the problem began he was incredibly rude and pushed Tina and Gabriel around as though he was his servants. I got fed up with him and asked him what was his problem. He told me they were bast*rds who didn't have any family and it was disgusting how he had to play siblings with them. He then blamed my wife infertility because he didn't have bio siblings. I was really upset and told him to get out of our house and not to come back till he respected us. He was pissed and said "I don't need a family if its someone like you." This was the last time I have seen him.

For the first few weeks he didn't respond. We got worried and tried reaching out to him but he told u to F off and play with the bast*rds. For thanksgiving we always went to my parents house. That year we were not invited. My family had heard from James and while they don't blame us they have a soft spot for James. We haven't been invited for any other family events since. We do make the occasional trip to our parents but they seem more wary of my children now, when before they treated them as if they were the whole world. During winter we found out James had been messaging Tina and called her things I am not allowed to repeat. This completely undid years of therapy and Tina was held back a year. James has since graduated with honours. Our whole family went to his graduation but us and from the pictures they all had a great time. This broke my wife and she cried herself to sleep for a week. James has also got a great job in a bank with a six digit salary. My wife's family has also supported him and paid his down payment of his house. They will not be helping Tina or Gabe. Even our neighbours have been treating us with contempt and we are looked as the people who chose to kick their son out. They called us aH. My family is a mess and I think we are on the verge of moving and going NC with the rest of our family. My wife continuously cries saying she wants to hug James and be at his wedding and meet his future children. I feel terrible not seeing my own son, but he has done this to us and is completely happy. My extended family have told us even though James may be in the wrong they will support him because he is blood.