Um - not to be a B*tch, but there are cheaper schools out there. Medical education will be what YOU make of it - from what YOU put into it.
If the money is going to be a real stressor for the family, discuss other options with your son. That is a lot of money for him to have to pay back when he's done - not to mention the interest.
We all have dreams, but when it comes to this much cash - one must be realistic.
Also - not to get all wierd...but if something is causing a lot of stress and not working out despite all efforts - I take that as a sign that, perhaps, it's not the right decision to make. He doesn't have a choice if this was his only acceptance...so, you just have to bite the bullet and borrow or he needs the military. However, if there is any way he could consider another school.....