By "beside", do you mean same enclosure or just beside another one? If it's just beside another one, I have 80+ snakes within 15' of each other, so that shouldn't make a difference. The little guy might hold out until spring and that's not a huge issue. They do that. They're made to do that. Your cage conditions sound pretty good. Is he in a tank?
I would just keep offering food every 2 weeks or so, don't handle him too much and try not to sweat it. I would bet ball pythons <b>not</b> feeding causes a good 80% of all snake related swears! LOL