A little confused by his post, did he get his ACL reconstructed too? or was it just meniscectomy/meniscus repair? 3 months to return to running is pretty fast for normal people but I guess he is an elite athlete with elite athlete resources. Curious how he got this knee injury... I know he likes to ball every once in a while maybe it was a bad land during a basketball game.
A good point of comparison would be Abby D'Agostino/Cooper who famously tore her ACL/meniscus during the Rio olympics. She came back just fine and had that great solo performance to reach the qualifying standard during trials last year. Would worry more about long term arthritis with high mileage training on a reduced meniscus, but hopefully he has a good team around him to watch out for that.