First and foremost he will need to take some art classes. These classes will probably be pushing him to draw realistically but even if that is not the "style" he is interested in he should take it seriously because a good foundation will be necessary. Learning to draw realistically teaches how to match shapes, values and colors so that he can draw his images with more accuracy.
As a college illustration professor (I graduated with my BFA in Illustration with a minor in Painting in May and started Grad school in July.....I've been teaching since last August) the most common thing I see is students who are interested in cartooning who do not take their drawing and/or life drawing classes seriously. They think that because they're interested in drawing in a cartoon style that drawing realistically is of no use to them......WRONG! Those are the students who wind up not able to cartoon well! We have a number of students go through our Illustration program who wind up in the tattoo business.....it's the one who take ALL of their classes seriously that wind up doing well.
If your local college doesn't have a really good art program he may want to consider going elsewhere because a poor art program won't get him anywhere.
Feel free to PM me if you have any questions.
You took the words right out of my mouth. It is a tough economy, but if your son really has some talent he can make a good living as a Tattoo artist. I would really try to get him to reconsider abandoning baseball if he can get a scholarship, because money is money, but in the same breath I wouldn't push him. If he is really serious about art and you want to support him getting him enrolled in classes is key. I would also but him lots of supplies and make sure he is honing his skills on his own time as well. If he really wants to compete he needs to be working on his craft everyday. It might be worth taking a look at Utrecht
to save some money on supplies, especially if you buy in bulk. It's really great that he found something he is passionate about, and its even better that you support him. I think that's one of the most important keys to success. Good luck! I hope it all works out for him.