He won’t have instate tuition until his mother has been here a year. That would not matter for Colorado College, an LAC in Colorado Springs, or U of Denver. There are plenty of other smaller private schools too, like Regis and Colorado Christian College.
Plenty of state schools too, but it is late to be applying and of course OOS tuition - CU in Boulder (also campuses in Colorado Springs and Denver), Colorado State in Fort Collins (also campuses in Pueblo and other smaller ones sprinkled around), Western State in Gunnison, Fort Lewis, Adams State, Mesa. Lots of community colleges.