For Computer Science, at What Point is it Advisable to Consider Cost or Prestige?

What I find interesting is my son goes to Bama…tons of smart kids…but no rank in CS. Got into Purdue. He’s got a 3.75 - but has at times seriously gotten his a$$ kicked but somehow keeps pulling through.

If curriculums are generally similar - would someone who graduated say - in CS at Southern Illinois have struggled at CMU? or conversely, would someone who was smart and talented enough to get into CMU or UIUC - but they struggled there - would they then struggle at Southern Illinois as well even thought they could have been a B- student, a low ranking, average rigor and still have gotten in…