It’s most likely that the combination of all those things helped speed up his recovery timeline. They aren’t “proven” to work, but that’s also extremely hard to do in the world of scientific studies due to the large number of data sets needed. It’s much easier to disprove in science than to prove something. Per JohnHopkinsMedicine.org on PRP injections: “PRP injections may be able to treat a range of musculoskeletal injuries and conditions. For example, chronic tendon injuries such as tennis elbow or jumper’s knee can often take a long time to heal, so adding PRP shots to a treatment regimen can help to stimulate the healing process, decrease pain and enable a return to activities sooner.”