Hi,
I would worry if the cause of death of the other frog was unknown.

Double check that all temp and humidity settings are in order.
Feed them well. I would not ration any food.

Make sure he is pooping-though! Hang out after lights out and watch for this event to take place!

NOW THAT'S A GREAT WAY TO SPEND SATURDAY NIGHT !!!

Sometimes these things are temporary. Keep an eye on him.