Dad Smells Bad

QUESTION: "Dad is starting to smell bad. He bathes and changes his clothes about once per week. While he is not unhealthy, he and his house have acquired quite the odor. He needs to bathe and change clothing a bit more often. How do I approach this delicate subject with him? Since I am the oldest of my siblings, I am the designated point-person in our family to watch out for Dad. He is a very proud man, and I do not want to deal with this situation." - READER