@valengist,
When my wife died my father kept phoning me up asking how I was. It got a bit much. I'd spend all day dealing with things, try to relax in the evening by watching some telly to take my mind what was going on only to have him phone up to remind me of how awful things were.
In the end I had to tell him to stop phoning up because it wasn't doing any good at all.
Let your friend know you're there for him, but leave it at that. Sometimes people don't want to talk about things.