Parent Plus Loans cannot be in your son's name. It will always remain in your name.
If you want your son to pay the Parent Plus Loan, I would get an agreement written between the both of you. But he cannot take out a Parent Plus Loan, you will still have to have it in your name.
Sallie Mae used to be to "go to" loaning lender 10 years ago, but they are now Nelnet.
I had 4 kids graduate college. My oldest have Federal Loans in the 2% range. When my youngest attended the Federal range was 6%.
But the private student loan company's were all around 13%. Since she was our youngest we really helped her out, and we also did with our 3, but
we really helped her out.
She roomed with 4 other girls in a TownHouse and her rent was $200 a month.
We bought groceries, we prepped food together and she would take half and we would take half-(Freezer-crock pot meals).
She worked 20 hours a week, luckily her employer set her up to do clerical work from her office in her home she rented. She worked for them since she was 16.
We put gas in her car, paid her insurance on her car, which we bundled into our car insurance for a cheaper rate.
It was a lean 3 years for all of us, but we did it. It helped that UW-Green Bay's tuition was $4,000 a semester. She got about 1/2 in Student Federal loans and we came up with the 2nd half between us.
Good luck with your decisions.
Hopefully when your son graduates, he will have a good paying job, sounds like he will have loans exceeding $25,000 or more, which is pretty normal, but he will be making at least a $300 a month payment towards his loans.