He'd have to blow an awful lot of money to wind up with more than 40k extra debt left over for 2-3 more years in a relevant extension of his associate's degree, especially if he's working at all while this is happening. Undergrad degrees don't generally require the gilded universities, and he has experience already beefing up his resume. Does he have a sponsor, or does he know where or for what, exactly, he's hoping to be hired?
If you're going to retire in 2 years, he wouldn't even be done yet (assuming Jan semester start). It would not likely seriously impact your retirement to make his payments that year, say, instead of figuring out how to give him 20k tomorrow.
All he has to do is fill out a FAFSA to see what grants he qualifies for. Then he applies for loans federally to cover whatever grants don't, and scholarships can be used to pay down those loans as well. Those rates are better than you will probably find privately (5.05-7.6% until July 2019). If he qualifies for subsidized loans, they're interest-free while he's in. Fastweb.com is a list of more scholarships than you could ever want to apply for, which may also help.