Let's see 12,000 miles..is that New Mexico, Moon? LOL Dot.calm had good advice, I just couldn't resist the rib!
I would have your boyfriend talk with his doctor about New Mexico. Ask about the potential dangers of being in high altitude, the precautions to take, and what steps he needs to do if he takes ill. Google for names and locations of hospitals in the area you're visiting, especially those with an ER. Do not go unprepared.