Yes, but the squirrel was kept because the owner killed their mother with a car on accident. This is not a case of "wanting a pet squirrel so badly" but trying to rectify a tragic accident.

Trying to rectify a tragic accident is getting the squirrel to a rehabber. He wanted a pet squirrel.

Professional medical care == medical care. Treating that sort of injury requires some training, but it's a far cry from the extensive and critical medical procedure you're trying to sell it as.

A tail is part of an animal’s spine, not an accessory. Go find a vet that thinks any exposed bone, much less an exposed tail bone, is something you can bandage at home and forget about.

A juvenile squirrel without a mother to learn from doesn't have a way to learn those survival skills without human intervention which will result in "lost their fear of people".

Rehabbers use techniques to keep animals from becoming habituated to humans and maintain their wild instincts, mainly keeping them away from humans as much as possible and not treating them as pets like this guy did.

What education and certifications would those be?

Varies by state, but they’re certified on the state level and it usually requires at least a few years of college.

Animals aren’t toys for people to keep and play with if they really, really want to.