so sorry to hear, i see guys have covered already the hospital set up and soaks. i just ask this - do you know where these frogs came from? WC from one place or from different? what you described sounds like toxic out along with red leg (septicemia) very common for frogs living in very crowded cages. i hope he'll pull through.
if i were you i'd separate all frogs in hospital set ups to quarantine each separately. you can make these from a regular plastic containers, very cheap and easy to do.