I'm very glad to heat you're trying to help out with this dog! Good for you!
It is very, very manageable to live and provide a secure atmosphere for a blind dog. Many dogs (besides sighthounds I'd say) rely on other senses besides just vision. We all know that dogs have noses that are thousands of time stronger than human noses, so they uses this sense to their advantage. It may take a little while to get used to, but your dog will soon be able to maneuver just fine in your home. Just don't move furniture around much. He will almost have a visual image in his head of where things are located. I wouldn't keep him on a second floor though, unless you have a puppy/baby gate. You don't want him falling down the stairs. Otherwise, everything should be just fine! Remember though, just because he's blind doesn't mean he shouldn't be able to enjoy the joys of life like any other dog. He can still be taken on walks in the park. He will much enjoy himself with the benefits of physical exercise as well as encountering an abundance of new smells! Make sure to watch out for cataracts though. If these form they could be painful and the eye would need to be removed. In this disease, dogs generally do fine with adapting to their loss of vision because it happens gradually.
Here's a very helpful website I recently came across which is designed specifically for blind and deaf dogs and their owners. I recommend checking it out;
http://www.blindpets.com/
In the meantime, here is an article I found online about the specific illness your future dog has;
PRA in Dogs - Animal Eye Care
Although this disease currently has no cure, there is certainly something you can try which may or may not delay the progression of this disease;
There is an antioxidant / vitamin supplement, Ocuvite, the MAY have beneficial effects on retinal cell health and slow or alter progression of retinal atrophy, though there are no studies demonstrating its efficacy in dogs, and it has only rarely been shown to have efficacy against a different type of retinal disease in humans (macular degeneration). Its administration is unlikely to harm dogs, and may help.
Hope I was of some help. Good luck.