I have two elderly parents. Both are relatively self-sufficient. But my father frequently gets cold and turns up the thermostat. My mother, on the other hand, is burning up at the same temperature and wants to open the front door. They cannot be in the same room for long.
https://www.agingcare.com/search.aspx?searchterm=one+parent+hot%2c+one+parent+cold
They will provide insights into why different people feel cold and warm while in the same environment.
I think the best strategy is to try and create different areas for each of them if possible. Set up a "man cave" for your dad in a spare bedroom and furnish it with comfy chairs, tv and a space heater, leave the rest of the place at a more comfortable temp for mom (and probably everyone else lol).