You're going to want to consult a labor and employment attorney about this. We're now talking about a situation that interacts with state and federal labor laws, particularly FMLA.
But here's the thing: if you aren't returning to work, your employer may not be under any obligation to continue paying for your health insurance. The FMLA does provide that an employer can't cancel your health insurance if you're temporarily out of work, but it does require that you go back at some point. If you aren't going back and aren't likely to, your employer may well be able to terminate you and your benefits. Figuring out whether or not this is true is why you need to consult a labor and employment attorney.
This answer does not constitute legal advice and does not establish an attorney-client relationship.
The other poster is correct; you should contact a labor and employment law attorney to review your case.
Even if your employer stops paying for your coverage you should still be afforded protections for continued coverage under COBRA .