Is it the temperature or the size? Your comments in the thread seem to indicate its about the pad's performance, not its size. I have a 12x24 sunbeam pad and its really great. I mostly only use it on warm to low unless i'm in a lot of layers of clothing.

What IS hot enough for him? Scalding showers? A hot tub? If you figure out what does feel good maybe you can reverse engineer to your solution instead of just getting more and more expensive heating pads.

This is the pad i have: https://www.amazon.com/dp/B00474Z0Q4