I hope he had the time of his life.

I don't see anything wrong with this. I've had a few funerals where I don't actually know the person that passed away and would feel awkward going to the funeral (like the relative of a co-worker), but would like to do something nice for the family. The drive-by viewing/guestbook signing would be a nice option to have.

Side question: what is proper etiquette for attending funerals? I feel awkward going to the funeral of someone my husband or I don't know even if it is a friend's parent or something. I know funerals are for the living and showing up is for them, but I already send a card and flowers (or donation if they prefer), so I don't know if that is enough or if I should go. The one time I went to the funeral of a co-worker's husband my other co-workers were offended I showed up since I didn't know him. They wouldn't let me help setup the refreshments or anything. It was so uncomfortable I just signed the guestbook and left shortly after the service. It wasn't a small/intimate service either. There were about 200+ people there. When my next co-worker's parent died she made it clear it was a service only for people whom she invited, which was everyone in the department besides two of us.