Sorry, I’m slow. So if he and is parents split the loans, then he will only have to borrow $18,500 per year, leaving him with, worst case (assuming tuition increases), $80K of loans. Not great.
Of course, when his siblings go to college, his EFC will go down to $35K, so $80K is really a worst case scenario. OP, when do your siblings go to college. Since Lehigh is full need, it’s likely he will get more grant aid when that happens, so the debt load will be reduced.
In this scenario, a lot of smart people who work for me took the private school education because they felt that the more personal approach was a better fit for them. Now certainly with Maryland Honors as an alternative, it might make more sense to go with the lower cost option. However, it doesn’t seem completely irresponsible to go the Lehigh route if the parents are willing.
Also, with regards to getting weeded out, one gets weeded out long before one incurs $100K of debt, so that’s really a non-issue. The private schools are less weed out schools. In particular Lehigh is quite manageable.