It makes him very uncomfortable. It is a situation that has been present for several years but seems to be worsening. He crawls into to bed mid day with a winter coat on and pulls the covers up and sleeps. Dry have been consulted. Thyroid is "normal". Any ideas or suggestions?
I think in general people tend to like/need more heat as they age. Warm clothing in layers that can be peeled off as necessary can be helpful. Turning up the thermostat (not necessarily all the way to where he can be in shorts) a bit might make him more comfortable.
My mother was always cold. She always wore a sweater and always had a blanket over her lap. (She was in a wheelchair.) Her hands would get so cold she didn't like to take them out from the blanket to play cards or color, etc. We got her some fingerless gloves, and that helped a lot. Other people in the NH were envious (cold hands are common) and we contributed several to use as bingo prizes.
I'm so sorry to hear how cold your 93 year old father is feeling. I wonder if an electric blanket might be helpful. I would consider getting a second or third opinion and have his blood work reviewed. For my own dad, I would always leave the furnace on and keep the house a little warmer than normal.