Hawkgrrrl, I have some limited experience with special needs children. There is definitely some tension between setting expectations so high that they will never succeed and so low that they have nothing to strive for. The sweet spot is in the middle where there are opportunities to strive, achieve and fail – always with gentle support.
As with special needs kids so too with the rest of us. Just adjust the middle depending on our ability/disability.
Supposing that BYUI was “too much” for your son, it can be perfectly acceptable to take that off the table and support him to be successful in a more familiar and supportive environment.
I like your setting of expectations with money and see them as baby steps towards independence and full financial accountability.