Hermit Crab Care Question

I have a pet hermit crab. He is currently in a plastic hermit crab habitat. However I am afraid he will die of lack of humidity and heat. I can't get a glass habitat because my dad didn't want for my dorm room. My hermit recently has been climbing to the top of a cholla wood branch that I have standing vertically and has been sleeping mostly of the day and night burrowed in. He isn't dead because he still has a firm grasp on it. I am afraid to pull him off and hurt him but he hasn't eaten at all today. Some advice please?

I think with all the sleeping and burrowing, he's probably cold. I don't have personnel experience with hermit crabs, but I do have experience with plants. Put a blanket over the cage, and put it in the warmest room in the house. And since you have a hermit crab, could you answer my question " how do I convince my parents I want a hermit crab". Hope this works, good luck!

can you get a heating pad or anything like that?