If it is their stuff, their issues, they get to say what happens to it and what they want to do. We can give opinions and ask for things but unless we are prepared to take whatever when it becomes available, it can be imposing on others to make them keep it for us until we can. Your aunt has to be on the lookout for her own, ask for the rug when she wants it/before your grandmother wants to get rid of it. There will be other rugs :-)

I try to remember to only give my opinion on things that directly affect me, now.