FIL passed away recently. FIL (and the sons) were terrible about money in the sense that they were always throwing wads of money at each other. "Here let me pay for that. No really I INSIST." "No really WE INSIST." Yada, yada.
Typical situation: When everyone was returning to base for the funeral week, SIL spent $200 to stock up the MIL/FIL house with food for the incoming hoard (it was empty for the season when they winter over in the south). H gave SIL $100 because MONEY. Not sure why it was our responsibility to pay for stocking the house (there are 5 siblings) since we live in the same place and were not the ones eating all that food, but that's how it is. We're wealthy - it's not like it matters.
So people were spending hither and yon, and H and I had a discussion about whether everyone was going to keep track and start billing each other. We agreed that since MIL is not poor in any sense of the word, and all this tracking and billing would be a PITA (and why?), we would generally have MIL pay for her own expenditures as we went along.
Since she has a hard time getting around, one of the things I am trying to do now is pick up things at the market once a week or when I happen to be going I ask if she needs something. I get a separate bill and have them bagged separately and she reimburses me when I take them in. Tonight, I picked up a few things she asked for and made dinner at her house as well. H showed up and tried to waive off the $10 for her groceries. I took the money because that was the plan. Now he is having fits and says I'm just greedy. I basically told him to pound salt.