Service Dog

As posted earlier my adult son lives with epilepsy.  He would like a service dog. Two doctors have written a RX for one.  But we discover that the already-trained ones are super expensive ($30,000 and up !) and even if we had the $ the wait is too long. His Texas aunt used to train service dogs & possibly he can go there for a week or two to get started, but we're wondering

(1) Can you recommend Petco or Petsmart classes/instructor who might be helpful for son & dog (yet to be found)?

(2) recommend books, web pages, even youtubes ?

(3)  other recommendations?

Thanks for your time & consideration.