Welcome to PC bella88
Isn't it so hard to watch someone we love going through hurtful situations and not really be able to help them solve those situations?? I understand where you are coming from.
I think Rhapsody is right in being there with open ears and arms when and if your bf decides he wishes to talk about the situation. Other than that, there is nothing you can do to make the problem go away.
This is between your b/f and his dad. The best thing you can do is be there for your b/f and not harp on the situation. Let him process things in his own way, he will come up with his own solutions in how best for him to deal with things.
Remember, men communicate differently than women do. Most times they are not as verbal as women are when it comes to voicing their concerns, especially if they don't have ways of "fixing" things.
Like Rhapsody, my suggestion is to be there with hugs and lots of love and validation for how he is feeling. That will mean a lot to your b/f.
I wish you both well!

sabby