I should have mentioned this to you earlier, but one of the better vet offices is right over the lake from you....Louisiana Veterinary Referrals. I've had occasion to use them twice and am very impressed with them. Here's the link....
LAVRC > Home
What I'm seeing from looking over this and the thread about you getting Max is that you had an 'apparently' healthy puppy for 3 days. Your posts mention nothing abnormal and the videos show a lively pup. This seems to be a sudden onset of symptoms, which kind of takes it away from something congenital.
Max's symptoms are alarming and he is in need of the best vet care at this time. The link I posted is a great facility with many board certified specialists and on site diagnostics. There is 24 hour emergency service available.
Best to you and prayers for Max.