Hi, Mary! My son was also diagnosed with primary FSGS, and all the meds didn't "work". I finally found an article on the internet about how asymptomatic proteinuria can be an indication of Dent's, and we took it from there. We're just starting him on thiazides, although we haven't had a lot of kidney stones. He seems to have a different mutation, one that has other issues.
Where are you located? We are in Oregon, USA. We see our local neph here, who is very good, but we have also been seen once at the Mayo clinic, and the Dr. we saw there, Dr. Carla Monico, will follow Mason, too. I encourage you to contact her, since I found her to be very helpful and interesting. I expect you would too.