You can't rule out Prostate Cancer without the full range of tests and even then not be certain.  It's a bit of treadmill once you get on it and getting off is difficult.   His psa reducing from 36 to 13 in a few weeks is promising.   Also that he had a temperature and other symptoms gives the impression there was an infection.
The private consultant offered the test that you wanted so that's good as well.  I can understand you wanting that test as I investigated a private MRI test when pains suddenly came on in my hip and that was just after I'd had an MRI.  I found an article in the Daily Mail website about 3 urologists who got prostate cancer and one said his first symptom was a pain in his hip and he knew what it was.  Better not to read such articles.   The hospital kept telling me the pains were a sports injury, and actually they were right, but I was very worried for a few months as it took 6 months to get well enough.   I thought the hospital staff were humouring me but they did it quite well.  The GP said it was arthritis and gave me a psa test, as it was then well post op and should be near zero which it was.  Fears can get magnified. 
Edited by member 04 Aug 2019 at 23:22
 | Reason: Not specified