FHNO (broken femoral head)

This adorable little kitten was rescued by us after being hit by a car twice! He was left for dead, but we saved him. We didn't know if he'd make it; he was bloody and beaten. After a visit at the 24-hour vet visit,  he seemed in good shape considering the circumstances. After x- rays, we learned he has a broken hip (femoral head & neck ostectomy, FHNO) and needs surgery. He is only 8 months old. This will be a great expense but we want him to be able to walk well again and be out of pain. Any help is so appreciated.