Managing people ia hard, especially managing family. So many emotions to navigate, feelings to avoid like land mines. Although it feels good that someone trusts you enough to pour their feelings on you, but it can get stressful for the listener.
Try this: when presented with a problem, especially a complaint abt someone, listen actively to the complainer. Make sure you can empathize with them and try to put yourself in their shoes. Next, say, “I know this is hard, I know how you feel…,” then ask them for a solution. “What do you suppose I should do?” “What makes sense to you?”
This asks the complainer to reflect inwards and think about the problem clearly. Most of the time they will agree there is nothing wrong, or they already knew the solution. People are just people.