Tell him to ask the doc about a "Cryocuff"... its a thing which straps around the knee and is fed by a pipe from a thing which looks like a thermos flask with a pump on it......you fill the flask with ice cubes and water and just top up the cuff now and again with the pump....
It will make a big difference to his recovery time !!.... I think you can hire/borrow/steal them form the hospital...
Cheers
Rob........