Do you have to go to college to be a vintner?

Most likely, yes. Some college advisor positions require bachelor's degrees, but typically, they require a master's degree.

To learn how to teach. Just because you know stuff, doesn't mean you know how to impart that knowledge to others. You also need how to develop lesson plans, make a syllabus for the school year ,and...

You should go to college. Some common jobs require you going to college and getting a degree.

Assuming it's your son or relative, all you have to do is tell them how difficult it is in the real world and ask him where he pictures himself in 5 years. Then print out and hand him a Mcdonalds...

Yes.