We've had the crab's for 1 1/2 years...thought we were doing pretty good. But we just lost a guy

I live in washington state, so we are in summer right now. 2 weeks ago I did a deep clean. Cleaned the glass with water and vinegar. Boiled all the beach rocks, new coco fiber, baked in the oven. Baked the coco hut, logs and moss pit made out of hemp. Everything that I would regularly do. Nothing is different or new besides the coco fiber.
2 of them have already molted and come up. They seem to get "happy" and molt whenever I change the coco fiber and they come up pretty fast.
The biggest and darkest guy I have had been sitting on a rock for the last 3 days, drinking fresh water. Today since he was still in the same spot, I decided to check on him and touch him. No movement. I took him out and he fell easily out of the shell. Looking at him closely, I see maggots on his abdomen. Not sure how long he has been dead for...
I have noticed that there are fruit flies in there and am having a hard time getting rid of them.
Since the deep clean the humidity has been very high (85-90%)and am having a hard time getting it to go down. Keeping the lid slightly open during the day is probably how the fruit flies have gotten in there. The other thing I have noticed (even before the deep clean) is that since it has been so warm here this last month, the crabs have been out and very active even during the day.
Im sad to loose this guy..he was a favorite with the biggest personality. I will take pictures and post them if anyone would like to see them. Not sure if it was male or female or even what kind it was. I loved his dark red coloring.....We will miss the little guy....