DEAR HARRIETTE: My father died a few years ago, and my mother told me that she has met someone who has been taking her to dinner. She wanted to make sure my sister and I would be OK with that. She and my father were married for 35 years, but he is gone. We miss him, but I don’t think she should be restricted from dating. She is still vivacious but also lonely. My sister doesn’t agree. She says my …