I think my husband is a little similar. Although without the alcohol issues, his father would get angry and abusive.
DH has two sons from previous marriages and I have my daughter.
The problem is that he didnt have a father that taught him HOW to behave as a good father figure. It isnt that he doesnt love them, but he was never taught how to show it. Our problem comes in when the boys needed disciplinary actions. DH just couldnt do it. To him, getting angry means losing control. He was never taught how to discipline without the violence as a part of it.
My daughter loves him, and they have become close over the last few years. But again, he doesnt know what he is supposed to do with the emoitions, how they are supposed to translate into actions.
I just keep reminding myself of that. coming from an abusive childhood myself, there are things I am deficient in because it wasnt something that was taught in my family. Forgiveness is where I am deficient. If there was a problem, it was ignored, instead of dealt with and forgiven.
Just keep that in mind, and at his age, it is hard to learn what to do with things you never knew before.