Six year old with Stargardt

My six-year-old nephew was just diagnosed with Stargardt disease. What scares me the most is that he got it so young and how fast it progressed, because his sight was not that bad just a few months ago. I’ve been going through the internet, and from what I’ve found, most people seem to be diagnosed at much later age and because of that I am scared of the worst.

From what I've found, people with this disease lose their central vision, but in most cases their peripheral vision remains. I can’t really imagine what it’s like—can someone describe how functional life with this condition can be?

Is there any hope that this disease will be treatable in the future—something that could reverse the damage and restore vision (or at least make it better)? I don’t know if I can bear the thought that he might go completely blind at such a young age and never be able to recognize the faces of his parents or sisters again.

Thank you so much for any answer.