Melody, knowing whether or not your shoe is on is mostly a function of the sense of light touch. We have other sensory nerve fibers that give us feedback of deep pressure and proprioception that help us when we walk. However, when nerve damage is complete and we loose this other sensory feedback, we can actually loose our ability to walk or have to rely on canes or walkers as well as using our sight for feedback.

I would recommend that he try Crocs as slippers. If they aren't warm enough..... I wear down booties that have a foam sole.