Hermit crab molting accident?

Question
QUESTION: I have three hermit crabs and all recently molted. The first one to molt either had a surface molt or a partial surface molt. I found his exoskelton scattered on the top but when I noticed it, he was already underneath the water dish buried. I was worried and checked on him to verify it was defintiely He who had molted. I could barely see much because he was freshly molted (therefore very small and in the back of his shell) but saw his antennae move so placed him back under the water dish. Next, my other two hermit crabs molted as well. The other two crabs have both since came back up but the first one never did and it has been over one month. Finally, I dug him up to see if he was alive and I'm not sure! He definitely has NO odor that would show he is dead but he has not moved AT ALL and all I can see is one long armor leg in the shell. (I think that is the really long skinny one) I don't see his pincher or any other parts. He is WAY back in his shell and must be a tenth of the size that he was before for me not to see him. I don't know if he is alive or not though. He doesn't move AT ALL, even when I touch the one leg. He hasn't come up for food or water either. What should I think? What in the world could have happened to this guy?? I have since placed him back in the same spot under the water bowl and am just going to leave him there in case he is alive and regenerating the missing portions of his body. I am just worried because there is NO movement or changes and it has been over a month. No movement at all even from the one leg or antennae. HELP!!! What is going on?

ANSWER: Does he smell like anything?

---------- FOLLOW-UP ----------

QUESTION: He doesn't really smell like anything and he definitely doesn't smell BAD.  There is no fishy odor at all, which is why I think he may be alive.  I have been wanting to submerge him in water but was afraid if he's alive that this will stress him.  He was a larger crab to begin with and now looks SMALL in the shell.  The only part showing is one long skinny leg, that is it.  He is FAR far back in the shell too.  It has been 6 weeks now and no movement.  I have no idea what possibly could have happened.

Answer
This is a tough situation and I can tell you the water test doesn't always work. I had a crab that I left in for several minutes and no activity and pulled them out and was going to throw them away when they got up and started walking around!

I would just wait. Is it a small crab?