Please help me with my cat!! he is really getting hurt?

You probably need to get Fred to the vet to get him checked out. Sometimes, cat's fight wounds can abscess and cause more problems. You won't be able to stop the fighting outside unless you're there every minute with Fred. I had the same problem with my cats and I ended up keeping them inside. You should do the same, at least for a little while, especially since Fred is declawed and can't defend himself. Good luck.