If you CAN get your friend to talk to him or someone to help him realize how cowardly he's being by filing it would help a lot.
I am sorry he' said what he did say... I understand how unpleasant that was to hear... but I suspect there was a LOT of other things that he was told that he chose to ignore and focussed on that one thing... if I were counselling him I never would have said that in the first place. It's just as destructive.
He really is drowining out there and needs a positive influence on him right now... If I were there, I would have been happy to meet him for a drink and give him a heart to heart... he really needs that, its sad the one influence that has the most impact on him (his father) is completley ignorant and useless.