Hello and thank you for the opportunity to assist you. My name is ***** ***** I will do my very best to answer your legal questions.
I am truly sorry to say that if you have used all of your FMLA leave, then you would have no recourse if you are fired for missing any more work, even if the reason is due to a health emergency. The FMLA is the law that provides you with recourse in this type of situation. So, when that law no longer applies because you have used all of that leave for the year, then there is nothing else to fall back on from a legal standpoint.
Of course, you may want to remind your employer that if you are fired for taking sick leave due to a medical emergency, then that could be a public relations disaster. In other words, you could let the local media know that your company fired you due to you being forced to miss work while having a medical emergency. That wouldn't make the employer look good in the local community.
So, while you would not have legal recourse against your employer, you may have other ways of pressuring the employer to do the right thing.
Does that answer your question? Please let me know if you need clarification, as I am happy to continue helping you until you are satisfied.