Scourge's Foot Surgery

Scourge is 17 years old 105 lbs, I've had him since a hatchling and he recently injured his leg in April, I took him to the get right away thankfully there were no broken bones or circulation problems but their was nerve damage to his foot so he can't feel it anymore, and he can no longer walk with it. The surgery is to fuse his foot bone to his leg bone so it's in the proper stepping position, and then after surgery he'll have physical therapy. Right now his  leg drags and this it's rubbing his scales off and spikes down to the meat so the surgery is a must. I have a grand saved for him and I'm trying to save, and I'm working out a payment plan with the vet, but still need a bit more. It's $4,855. for his surgery and his PT combined, it's 2,400 down payment to do surgery but I'd like to put down three so I can have lower payments because I'll still need to take him for checkups afterwards. He's had a week of physical therapy already which really helped a lot and got him moving the leg again, I even doing physical therapy with him at home, but since he can't feel his foot he can't flip his foot out to take the step so he lets it drag which is causing more harm on the scales and spikes of his leg. With this surgery his foot will be permanently flipped up and will be able to catch the ground. I will continue to take him weekly to the been to change his splints because they wear down as he moves, and do his PT to keep his leg strong for surgery. Thanks and we appreciate all the help!