HCA: Hermit Crab Association

Help please. My little hermit crab has finally had a molt. Just a few days ago me and my boyfriend got our crabs new stuff for the tank(things to crawl on and a bigger hidey home) while digging around I found my freshly post molted crab. And his exo. I replaced him back under the sand and threw away the exo not knowing that was their source of strength and calcium. Today I checked on him bc I saw a fellow crab with a crab leg. I wanted to make sure he wasn’t eaten so I dug back down gently and made sure he wasn’t dead. He’s very bright in color and still alive but with no source of food. I tried putting some chopped shrimp down right beside him hoping he smells it and digs to it so he can eat. Will he be okay? (ISO tank isn’t a option bc we have no where or way to keep him safely stored alone) please help.

This is why we say that if a crab is underground, not to disturb the sand.
Do not re-bury a crab - you cannot replicate their molt cave, and they will suffocate if buried with sand. If you buried him and then dug him up and then buried him again, he may not be strong enough to survive.
You need to isolate him from the other crabs, so that they don't kill and eat him. You can do this with an empty margarine container inside your main tank, with holes cut in the lid. You will need to provide food with calcium, and keep him in the dark container, and hope that he eats the calcium and hardens up. Egg shells, cuttle bone, if you can get some ground up exo or shells.