I’m middle-aged and have one brother, a few years older. Our parents were happily married for nearly 50 years when our mom suddenly died four years ago. Dad was 78 at that time. Dad walked around for the first few months after Mom died in terrible depression, as we all were, as we were all very close. Four months after Mom’s death, my dad went to a class reunion, and the next thing we knew he had hooked up with a woman, “Carla,” whom he knew from high school and who had been widowed about 10 years before. We got to know Carla fairly quickly because, against all better judgement, Dad sold…