At UNM, your son is guaranteed to get the Amigo Scholarship. The Amigo gives in-state tuition rates. In-state tuition is $7500/year, Room & board is $11-12K/year depending of what type of meal plans and dorm accommodations he chooses.
In-state tuition, fees, R&B will come in right about $19-20K.
UNM’s CS dept is ABET accredited and there are plentiful internship opportunities at 2 National Labs (Sandia in ABQ and Los Alamos in Los Alamos, NM), the Air Force Research Lab (in ABQ), Intel (in ABQ), and White Sands Missle Range (In Alamogordo). All the major Silicon Valley computer companies recruit on the UNM campus.
What specifically does your son find appealing about CU-Boulder? Skiing? Access to outdoor activities? UNM has all of those.
Frankly, here in the Mountain West, CU-Boulder has a reputation for being VERY stingy with aid for OOS students, as well as being a big party school.
If your son is open to a smaller, tech school environment, he may want to consider NM Tech in Socorro. It’s rated a “Best Buy” school and send a high percentage of its grads onto top science & engineering graduate programs.
With the WUE scholarship, it’s a tremendous bargain.
OOS scholarships at NM Tech
https://www.nmt.edu/finaid/nonresident.php