Some are very pricey. Do your research and check out the schools. I always tell my students to shadow in the field they are interested in first before entering school. It is a great way to know what you are getting into and you can build relationships for networking.
Make sure he takes the needed steps to do the research and make sure of his decision. Missing part or all of his senior year is a big deal. He needs to be able to make this adult decision with an responsible attitude.
(I work in the medical field and my students are from health care related fields but I give the same advise to all students looking into careers or career changes--I didn't want you to think I was in the field of cosmetology. My cousin went to school a few years back and told me there was some differences in school costs)