If your mother uses up all her sick and annual leave, she can only miss work, even for recovery from a stroke, if she is eligible for unpaid FMLA leave and uses it (and then, obviously, only for up to the 12 weeks FMLA provides). The law does not require employers to retain employees for miss work without using FMLA or PTO (paid time off) and they may terminate employees who do miss work without FMLA or PTO--or they could suspend the employees, reduce their hours to reflect the time they are actually able to come into work, or take some other step short of termination. (You can find the FMLA eligibility criteria on the U.S. Dept. of Labor or DOL website.)An employee must make "reasonable" accommodations for employees due to their medical conditions, but a reasonable accommodation is a change in policy or procedure, or the provisision of some assistive device or technology, which is not too expensive or disruptive and which still allows the employee to work essentially the full hours she had been working and to do the core or important functions of her job. If someone cannot come into to work, can only work shorter hours, or cannot do the core elements of her job, the employer may terminate, suspend, reduce her hours, transfer, demote, etc. her.For a definitive answer as to her rights, your mother is strongly encouraged to consult with an employment law attorney who can discuss and evaluate all the specific facts of her unique situation with her. All we can say that is that if your mother's stroke and recovery therefrom is causing to her to miss more work than she has leave or PTO for, or is preventing her from doing her job or working full time hours, then it is entirely possible that the employer can reduce her to part-time hours (or even in some cases, as stated, suspend or terminnate her), and a reduction to part-time hours would clearly impact her benefits. We are not and cannot say that what they are doing is legal in her specific case, since it depends on her condition, her eligibility for and (if eligible) use of FMLA, etc., but we can say that based on what you write, this may be legal and she really needs to consult in detail with an attorney.