Me and my mom are trying to seek advice.

My mom is a teacher but just recently her back started hurting and now she can barley walk. ( she just found out she has arthritis) She feels like she can not perform the same duties as before. She already miss a week of work and has to go back tomorrow but she is still in the same pain. She feel like she needs some time off to at least heal but she is afraid that they will let her go or she is afraid of unpaid leave because she has a house and other bills to pay( I wish I can help her financially but I’m also barely getting by)

Please any advise for her!?