Re: As a friend, what do I do?
For me, the best thing any of my friends could do for me was to just be there. I will forever be grateful for my friends who just sat on my floor with me and let me cry, zone out or whatever I had to do. Its been 3 years already since my dad died, and I still have one of those friends who can read me well enough to know when its starting to hit me again and he just kind of judges when to either let me sit and zone, or if he should find some strange way of distracting me to get my mind off of it. Its amazing to know that you have at least that one person to be your rock, and it sounds like you may become his rock and his stability when nothing else makes sense, and that's a good thing.
Also, just being able to talk about my dad and not get the awkward glances from everyone is extremely helpful, and it sounds like your being as supportive and great with that as you can. It becomes really hard when you're trying to guard what you say because you don't want your friends to get upset and wait for you to start having a melt down every time you mention the person who died.
But overall, it honestly sounds like you're doing everything possible that someone else can do. There's really no right way to fix it. And with leaving stuff that his dad put there, just go along with it. I did the same thing after my dad died, but my mom decided that she wasn't going to put up with that and she started throwing away his things, and I honestly believe that that made everything a million times harder because she didn't let me process everything on my own.
So I guess my overall comment is that you should just be there for him, let him talk about his dad and enjoy the stories. And let him proceed with things that have to do with his dad in his own time and in his own way because forcing him to do something he isn't ready for can make things harder for him in the long run.