A man shouldn’t run down his dead father...ever.
Even if he was awful, just remain quiet and say something like you hope he has finally found peace.
Disagree on that. Depends on the father and many of which can be especially cruel or non existent. Father’s can be a POS just like anybody including mother’s and if they are they should be remembered as such.
Sometimes you’ve just got to be honest. This is especially true for the children of people with drug and alcohol problems. Because the genetics are there. And so might me other parts. If he needs that layer of separation to protect himself then that’s what he should do. Better than dead at 48 like his dad.