I'm sure you messed his leg up pretty good but bones heal and knees can be replaced. Odds are if this is in fact true he was seen by a general surgeon when he was brought to a hospital. The surgeon would try to stabilize the leg by inserting plenty of pins and rods or to anyone who understands orthopedics, the suegeon would construct an ORIF and external fixator. That's to say he would add all sorts of hardware internally and then secure it by encasing his leg in metal fixators outside the body. You may have seen this before on someone who has metal holding bones together or if someone has the metal halo around their cranium (skull). My best guess is that he would need reconstructive surgeries to get the bones of the lower leg (tibia and fibula) back in alignment and then they would reconstruct his knee. You probably busted his knee cap pretty good and maybe they replace it with an artificial one. His knee may be pretty injured and shattered so they might do a full replacement or just partial (hemi arthroplasty). They could clip off the shattered condyles of the femur and replace them and resurface the tibia. It's remarkable what they can do to fix shattered bones. Now remember bones take 4-6 weeks to heal intiially and then momths of finalization and in these situations I've seen surgrons require patients to be off their leg (non weight bearing) with it hoisted up in Buck's traction to maintain alignment. He probably could be laid out for a good 2-3 months while he is healing and then may require multiple surgeries in the future. Within 6 months to 1 year he could be fully restored and in therapy to regain full function.

It's really a crazy story and it's hard to believe but if it did happen I could see your victim back on his feet after a few months. Odds are he is plotting revenge on you and your loved ones. Be careful. I work in physical therapy and see people that have been in bad accidents and motor vehicle accidents where they shatter legs, pelvis, and spine. Most people make decent recoveries but the journey is a hard faught one. Young people heal very quick and generally do well. Older people heal much slower and have less success. Seems your victim is young, he should fare well. Good luck. Just know that I would have done the same thing and probably would have done what you didn't do. I would have taken his life.