Early riser emergency!

[Akuma223]

A friend of mine found a gray tree frog again at school. He was sitting on the pavement where there has been salt all winter. I think he must have woken up when the weather got real warm all of a sudden, and If I were to release him he might not get back underground in time even if he wasn't injured.

He also seems to have a very broken back leg. It doesn't fold right against his body and when I examined it closely it looked and felt broken. He has an ill color to him, kind of sickly yellowish-gray, and his skin has a rough kinda dry texture even when I mist him. His breathing is also a bit more rapid than my other gray tree frogs. He is in a small container with moss and dirt right now and I mist him often, he does seem to change position occasionally in his container. he seems to have feeling in his toes on the broken leg. He seems alert enough, he opens and closes his eyes.

What can I do to help him that doesn't include putting him out of his misery?
I need to save him. Should he have UV light, soaking, extra dark, warm, cool, what? I really need to save him. Would the leg need amputating? I don't know....