DEAR ABBY: My son “Jeff” is wealthy and lives in another state with his wife and family. His wife has now moved her mother to where they live and she works for my son. Jeff and his family take vacations several times a year in the U.S. and out of it, and always include her mother or her father and his wife. Two months ago, he invited his sister and niece to go with them. They were very excited, but a few days later he called them and said his wife wanted her mother to go, so the invitation was ...