I'm sorry I am just now seeing this post, Marie. No, I don't have experience either, but I wanted to offer some *hugs*.
You mentioned he was feeling some guilt. I know this is a very common emotion, one of the stages a survivor goes through. I think the first is anger. It's probably true you two are heading into something too fast. He does need to go through the grieving process. I think he turned to you because you could offer help without...hmmm, possibly because of the distance between you, he felt there wouldn't be complications. Now it could be he's feeling slightly "adulterous". I would keep an emotional distance. Be his friend, want good things to happen for him. But don't cloud things with emotions. You have time. Be there for him to help him heal slowly. If you rush to put a bandaid on it, the scars will all still be there underneath.
Anyway, this is what it sounds like to me, seeing it all from a distance. What you might want to do is read about grieving, the stages of surviving someone's death. It may help you to understand his rollercoaster of emotions.