It is always good to go for conservative treatment and he is doing it the best way and we advice you to follow your orthopaedician.
With a long period of time and when all options fail you go for surgical intervention.
You can go for arthroscopic procedure of the knee which you can discuss with any good orthopaedic surgeon. Arthroscopy is also diagnostic and you can know if you have any other problem in the knee. Before that go for an MRI.
Take care!
What may be the surgical possibilities, because he is using all possible conservative treatment.
Rest and anti inflammatory drugs with ice packs would relieve you of pain.
If with rest to the leg with immobilisation would not relieve you of symptoms you should explore the possibility of surgery. Follow up near an orthopaedician for examination and follow up.
Taeke care!