Focal and segmental glomerulosclerosis (FSGS) has many different courses and many different presentations. There is not just one clinical course for all patients with FSGS. In fact, minimal change disease (MCD) has often been found to evolve into FSGS when patients are retested with a second kidney biopsy. It is suspected that the first biopsy just missed the areas of FSGS and hence a diagnosis of MCD was made. This is especially true of patients with MCD that is resistant to steroid therapy.
I am unable to offer any prognosis based on the information that you present. The fact that she has made it 26 years already, suggests a pretty good prognosis. Each person with FSGS is unique and has a unique clinical history and a unique prognosis.