If he likes Purdue and Clemson, Virginia Tech seems like an obvious one to add, sharing a lot of the same positive attributes.
Agreed that both CO Mines and CU Boulder would be pricey; Colorado State, however, is a WUE school and could be worth a look. Utah, as already mentioned, has great CS - many of the same virtues as Boulder, but much more affordable. There’s the WUE discount, or the path to residency after the first year.
The Nevada flagships are also WUE schools with strong CS. If he wants a more urban experience (although his list doesn’t imply that he does), Portland State has a great CS department also. Oregon State is also a WUE school, as are both U of Montana and Montana State.