Last summer I bought twould PP's from Petco, Harold and Biscuit, and one female PP from Petsmart. The two from Petco got along super well and we're almost like brothers
However, a week ago the slightly smaller brother, Harold had passed due to molting difficulties

Around the same time Biscuit had started chirping. I have never heard them chirp before. Do you thing he's chirping for his lost friend? Or is this all by coincidence?
He's not completely alone because there is the female crab in the tank. I'm curious to how much they bond with certain hermit crabs.