Sorry to hear you are facing this, it must be difficult to find out your puppy is going to go blind.
Here is some research I found and how Progressive retinal atrophy affects the Poodle breed.
I wouldn't rule out PRA due to his age. Some diseases in dogs don't progress by the book like they say. I do think you should possibly get a second opinion and of course research the condition more.
Im sorry to hear that about your Baxter though. I hope you guys figure out what is going on and your questions get answered. I would certainly try to get one more opinion if your able too. Good luck to you and Baxter. out: