I guess it helps if the tribe is a Nature tribe, but, no, there doesn't seem to be much you can do. I've tried baby-sitting elders and kept feeding them potions to make them well, but this didn't make them live longer than others. However, I've come very very close to getting a 90 year old. I had several die at 88 and 89, which was so frustrating. I think it might be a waiting game and eventually you get lucky.