Returning to the USA - so many concerns about insurance, costs and treatment

[moskids]

I am the mother to an 8 year old son who was born with double renal reflux level 5, cystic kidneys... He was given a urostoma at 8 weeks which was closed at 4 years old. He has one kidney that is small and does almost no work and the other is severely enlarged and is slowly losing function. We are currently at Stage 3a. We have been living in Germany for the past 17 years but are thinking of returning to the USA. We are on public healthcare and have never paid for a thing for him other than our general monthly insurance. We are wondering what will be the real costs in the future. I am looking for the price of general care including growth hormone shots, general tests and of course overall treatment. My questions are a bit general but I am not sure where to begin.