Crab not moving and other one is out of his shell

[WillP]

Hello. This is my first time posting.
I am a crab grandpa lol as my daughter moved out and I have been taking care of them for about six months now. They have become my little obsession. I take very good care of them making sure that their tank is at the right temperature, right humidity, and that they are fed well. They have two water containers, one salt and one fresh, w bubblers. I went up to check them last night and one of them was out of his shell and the biggest one is partially out of his shell. I picked the big one up and he is not moving, but he is also not falling out of his shell. He does have a very slight smell to him. I have increased the temperature slightly, but it has not exceeded 80* and the humidity has been around 82-83%.
I am wondering if he is molting or if he has died. Please help and thank you!

[curlysister]

What size tank are they in? What are you using for substrate, and how deep is it? How many and what type of shells are you offering?