Its been traced back to a vaccine. I can tell you either way you go with the drugs you may look at problems. I had steroids for 10 year and then cytoxan. I did not come down with lekemia. But i do have fibro/cfs now.
Protien in the urine can be a sign of kidney damage from mercury. Dont know if thats the case with you but its worth lookin into.
Im in heavy metal detox now for mercury and lead.
maybe get him metal tested, if positive do some energy healing on the kidney/adrenals (acuscope, diapulse, acupuncture, microcurrent etc.) and do a mercury chelation?