Hello

My parents are currently going through a divorce. My dad is completely broken. Basically a giant mess. Its been 2 almost 3 years from the separation and if she is even mentioned he goes off on a tangent about how she did him wrong and she's the reason for everything and the guy she is with too. She cheated on my dad after 30 years together. My dad takes medication but hes kinda like a slug all sad and moppy. Is there any books or tips to help him better cope? I cant keep walking on eggshells with him. Unfortunately there are times she has to be mentioned (like the fact that she is taking my youngest brother to Flordia for xmas so we have to adjust our plans to include him - note is he over 18)