[hocus pocus]

It's really nice of you to be supportive of your boyfriend. Sometimes going through a deceased loved one's possessions can be helpful to people. Encourage him to express his feelings; you could ask the about the significance of the ties he chose to bring home. If he has any pictures of his grandfather, he could make a scrap book or a document/poster to remember him by. See if you can get him to write a letter as though he's writing it to his grandfather as that's a good way to get some closure. I think the best thing you can do is to offer to listen when he needs to talk. Just being there to listen can do him a world of good.