DEAR MISS MANNERS: My aunt, with whom I’m very close, frequently tells me in casual conversation how wealthy her daughter (my cousin) and her husband are. How do I respond/react to that, if at all? I don’t want to cause a rift in our relationship. GENTLE READER: “How nice for them.” If you want to be slightly wicked, you could add, “I suppose, then, that they do a lot of philanthropy. What are their favorite charities?” *** (Please send your questions to Miss Manners at her website, www.missmanners.com; to her email, dearmissmanners@gmail.com; or through postal mail to Miss Manners, Andrews Mc…