$1 is a wonderful organization, they have lots of info and support for you and your son, and they even have a helpline where you can talk to a real person.
The most common form of rod-cone dystrophy is Retinitis Pigmentosa, and there's a ton of research and advancements.
You'll want to pursue genetic testing to identify the gene so that your aware of when treatments become available.
Everyone has provided really good advice here.
I'd just also point you to
$1 discussing when might we expect a cure (or should we).
While you want to be pragmatic and adapt, there is also great hope. So adapt, find a wonderful life regardless, and also know a world of medical researchers are working on real solutions for the future.
The best thing you can do for him is give him a wonderful childhood where education is loved and he's surrounded by friends he can grow up with.