You asked the same question twice.
Your son is in effect blackmailing you to pay for his health insurance when you should not be responsible for that. if he refuses to allow you to be released from his student loan obligations, and later fails to pay on his loan, the lender may come after you for payment. This you already know. if the lender comes after you for payment because your son has failed to pay, you have a right to seek reimbursement through the court system. Hopefully it will not come to that.
If you are looking for an attorney to assist you right now, this is not the forum. This is a general legal Q&A form. Look at the top of this page and click on the Find a Lawyer tab. You should be able to find many lawyers in your area who handle this kind of work.
Duplicate question. See the duplicate answer to the other instance of your duplicate question. Please try not to be so duplicitous. It wastes our time.
I am not your lawyer and you are not my client. Free advice here is without recourse and any reliance thereupon is at your sole risk. This is done without compensation as a free public service. I am licensed in IL, MO, TX and I am a Reg. Pat. Atty. so advice in any other jurisdiction is strictly general advice and should be confirmed with an attorney licensed in that jurisdiction.