I know a bit about St. John's in Santa Fe. I have a relative who used to teach there. I believe it's the same school but a different location. Not sure I am the best person to ask about it.

Although I'm far from an expert what I know about the St. John's in Santa Fe I don't think it would be any better or worse from other LAC's for a kid with executive functioning. It's university you are expected to get to class on your own, do your homework without prompting.