Another name for knees is Dr Jonathan Webb in Bristol, he is only private but superb. Sorted ACL in my left knee and ITB in the other !
Second a bike fitting – I used cyclefit as well and although they are expensive they are a superb outfit, incredibly thorough and I have had far less probs since.
IMHO he is unlikely to find a complete cure, he will always have probs, but he will find a way to keep them under control.
If he cant travel to any of the above suggestions and he wants a physio, tell him to contact his local professional sports club (football, rugby, etc) and they will either have sports physios who do freelance or they will know some
Best of luck