Do you think that in a relationship, that one or the other person adapts to the more dominant person?

My son has a wife who hates her mother, she is a very dominant woman and my son is the primary caretaker, homemaker and breadwinner in their marriage, His wife treats my son as if he's a complete imbecile and an idiot, she's been trying to get life insurance on him but because he told a doctor he'd thought about suicide previously she's mad at him for screwing that up. He he told his sister he's on antidepressants now, because his wife says he needs to be. He is rude and "fake" to his side of the family (who his wife considers to be "trash"). I've noticed during their 2 year marriage, he has adopted her attitude towards her family which is "fake" or polite as he calls it. He wrote me a very terse email suggesting I get "help" to overcome my issues with him, my friends and family as I am the one with the issues and that he is disappointed in me. He and I have always been close until his marriage and now he is "polite" if he talks to us at all. I don't suppose it helped that we were having this conversation after my sister ped away where my son told me he doesn't believe in God, life is cruel, "stuff" happens and I better get "cool with it". His email was derisive and bullet-pointed and forwarded to his wife for her review (his wife is an "Executive Lawyer as she likes to repeatedly remind both him and his side of the family). He told me my thoughts were baseless and rooted in my own insecurities - he's accepted no responsibility for his part in the conversation, he then embellished it to appear to his wife that that he had no participation in our conversation when all I said to him was that I didn't feel as if we were as close a family as we once were. I've never dealt with this with my other children. I've apologized for hurting his feelings, he's holding my grandson hostage, because neither I or "my daughters" (his sister) are good enough to see him nor welcome to visit them anymore. All I could do was reply to his email with "I'm sorry and I love all of you". He has not replied, I don't believe he will or can. Thoughts? Advice?