DEAR ABBY: My sister-in-law is a lovely woman — generous, with a heart of gold. Her husband, my husband’s brother, is a kind and gentle man who works hard to provide for his family. They do much for their community and seemingly have every moment of the day occupied with something. But whenever I’m with my SIL, she never fails to whine about where her husband falls short. Sometimes, she does it in front of him. It’s uncomfortable because I don’t want him to think I agree with her. Almost always the problems are minuscule. Example: The house is never clean enough, or he’s not doing X-Y-Z to he…