Yes. Honestly, med and dental admissions aren't that much different... :/ We have an admissions test, require letters of rec, shadowing, volunteer work, having research is good, we also apply in June, etc.
You live in Texas, and there are three big dental schools there that accept primarily in state students. So if your brother does the right things (I'm sure you can guide him in the right direction, like keeping grades up, studying for the DAT's, etc.) then he'll be fine.
Being a dentist also means helping people. People suffer from oral health problems and there needs to be someone to fix it. Personally, the humanitarian aspect of dentistry is appealing, and I like the fact that it requires a lot of attention to detail and hand work.