Prostate issues and early neutering
It is completely your choice what to do with your dog, you should not sell your dog if you feel attached. There's an ethics issue with selling a dog whose hips are not healthy, too, I don't know why the trainer would suggest it.
Despite being supportive of rescuing dogs as appose to buying, I am NOT supportive of S/N to 'prevent breeding'. You prevent breeding by keeping females in season contained. I had my dog neutered because he had a prostate issue due to not being able to breed, but smelling females in season, and I was not willing to 'release' him (I was 15, didn't seem like an option to me.)
It sounds like there are ways around that law, as people above stated, but it's an issue you will face with every dog you get. I would move, personally.