His Testicals are swollen huge, and his kidneys are failing

I am surprised you say that doctors have never seen anything similar to your friend’s condition!! I think he should go see some other specialists so that he is precisely diagnosed as kidneys and testicles are the organs he shouldn’t play games with.
As the matter of kidneys, has he had some problems urinating or has he noticed blood in it? Does he have the need to pass the urine more often than usual?
These could be the symptoms of some UTI and the condition caused by bacteria. I would always suggest that your firend does the urine culture and all the necessary tests.
Have the doctors told him that his swollen testicles are linked to his sick kidneys? What else did the docs say? I still can’t believe they didn’t say a thing nor even made an assumption! They must have gave some opinion, if so what is it?
I just cannot help much and all I can say and recommend is taking the urine tests to see if there are some bacteria present, then if the tests are positive it could be the cause of affected kidneys and the doctors should react immediately!