What should you do for a cat who has a broken paw?
This type of question puzzles me. What would you do if you slammed your hand in a heavy door and broke several bones in it? Sit around and type questions about it, or get to the hospital? Fractures hurt. If not set properly, they heal badly, and cripple the victim to some degree. Cat can't grow new paws any more than you can grow a new hand. Get the poor thing to the vet.
I would take it to the vet, then after they fix it i would nurture it until it can walk again