After losing my dad, the best gifts were those that made life easier when I was too down to deal with things. For instance, gift cards to Domino's, Pizza Hut, or local restaurants that deliver. When I didn't feel like dealing with dinner for the family, I could just call and have it dealt with. My mom received several of those as well and really appreciated it. If it feels too impersonal--and depending on how close of friends you are--you could put it in with a knit shawl or blanket. Something cozy and comforting.