Welcome aboard. This is a good place to hang out, listen and learn.
My son also expresses a lot of anger, and sometimes I really can't see what he is angry about. A therapist told me recently that sometimes anger stems from fear/anxiety.
It is so hard when you see someone who needs help like this and just refuses to get it. Yes, I think therapy for yourself to help you learn better how to deal with him would be a good start, especially if he won't go himself.
In my son's case (he has bipolar disorder among other things)he is quite different when on his medications.
I like the idea of a male role model to talk to him about seeking help. Not just for himself but for the sake of his baby.