Best course of action with relatives (especially with widows) is to have them set a price, then you either take it or leave it- if you bargain at all, then they feel taken advantage of.
Wife's dingbat cousin loaned us her old vacation trailer one time. We used it, fixed a couple of things on it, rewired the plug, and took it back in better shape than we got it. End of story? Noooo- Dingbat then lent it to another cousin to live in- she stayed awhile, then moved out in middle of winter, and the pipes froze. Dingbat thought we should give her the 50 bucks it cost to get the pipes fixed- no amount of explaining would convince her that it was the other cousins fault, not ours- after the third time she complained loudly to all who would listen at a family get-together, I pulled a 50 out of my wallet, and handed it to her, in front of many witnesses, and said "Now its done, right? No more complaining, right?" She agreed, and to her credit, never mentioned it again.