next time you bring him to play, take some video.
Orijen is a great food, truly worth the price. My suggestion there would be Acana, made by the same company, same quality but lower protien content. Most dogs do not take well to high protien unless they are burning it i.e. very active/working dogs. High counts of unused protein also lead to problems with kidney damage.
Did this dog come from a breeder? If so have you contacted them? Any health guarantee? Most responsible breeders will offer some type of helth certification or guarantee with dogs of breeds known to have health problems as a testiment to their breeding program. Seems to me as this could easily be related to genetic issue and at that point I'd go after the breeder. It's very common for breeders, of these currently popular or trendy breeds, to produce as many pups as possible with no consideration for proper blood line etc.
Glad to hear he is doing better and huge props to you for sticking it out and helping him be the best he can be!
Edit: I'd highly reccomend a product called Pet Kelp as an additive to his food, I've had nothing but fantastic results with any dog consuming it.
I've currently got him on Taste of the Wild, Pacific Stream and he took well to it. I'll keep Acana in mind, though, if a change in diet is needed.
Yes, he is from a breeder and compensation was taken care of a while back. Unfortunately, the situation was a bit unique and it made things a bit difficult. But, honestly, money is my last concern when it comes to a pet.