Oh nooo :'< I'm so sorry, what a horrible thing for you & Kirk to have to go through SO incredibly early on.

I cannot imagine how hard that must be for you & your little boy! I know, that keeping my 5 month-old quiet after his neuter is an immense pain, for 1 week... much less semi-permanently. I'm really really hoping that it will improve with growth, and his surgeries will be successful. Poor little guy! It's a shock that a pup with parents who are good & excellent rated could develop HD right away... wow. You should definitely call the breeder and inquire about previous pups and littermates, that is not in any way rude! If I was his breeder, I would absolutely want to know, and she will probably be willing to help you out. Is there a guarantee on his genetic health?

My advice (and I'm sure your Vets advice) is to get him swimming/doing low-impact exercise and building up lots of muscle, as often as possible. My Flyball trainers Staffy also had 2 bad hips at a young age, and what kept her relatively pain-free until surgery was all of the muscle in her hindquarters, from swimming and exercise.