L.A.
I really suggest your son and his father go to family counseling.. Or you take your son to therapy, so a professional can help your son come up with response and also collect data.
Our parents were divorced.
My father was a terrible parent. He also criticized us, our mother..
He did not even really know what was going on with us. He never attended anything we participated in.. If we talked about school, parties, lessons.. whatever.. he always had some dig to give us.
He just seemed to be projecting assumptions he and my stepmom were making.
At one point my mother suggested we go to family counseling with my dad and stepmom... And so my dad made the arrangements.. Boy did a lot of things come out in that session.. The Therapist jumped all over my father and stepmom about the way they had been speaking about our mother.
How my father was so critical of us, even though he had NEVER attended any of our schools or events. (he did not want to see our mother).. She essentially told him to grow up, act like a parent and deal with his own issues, before criticizing us.
She warned him, he was going to make us not want to be around him or feel comfortable sharing our lives with him..
He was stunned. No one had ever spoken to him so bluntly. But she was right. Once we were 18, we quit going to visits..
It is not fair to your son, to not have a voice. You take him to a therapist to help him have an advocate that his father will listen to, if he will not listen to you.