Help This Sweet Cat Save His Leg

We are raising money for this sweet boy to get his leg fixed. He is only a year-old tuxedo male cat and we found him on the side of the road in a box with his sister. They seem bonded, so we brought them to the vet together to discover he broke his leg. It happened when he was on a dresser, and he jumped up to grab onto something and he missed, fell back down, and landed wrong on his left back leg. Options are orthopedic surgery or amputation. We would like to save his leg the best we can, so anything will help. We have only had this bonded pair of cats for a day, and we’re trying to give them a good life. I would hate to not be able to get surgery for it. Right now we are raking up to $800 and that’s just for antibiotics, a splint, sedation, just to hold him up until he gets surgery. Anything will help. Thank you so much.