What action can we take when an employee is hospitalized for mental health issues?

Q:  “We were informed that an employee in good standing was hospitalized for [mental health issues]. We have placed her on suspension until we can gather additional information about what is occurring and her ability to safely complete her job duties. She had previously disclosed a history of mental health issues, but had provided a clearance from a medical doctor stating that she was stable and able to work. Is this a qualifying event for FMLA? Are we able to terminate her employee because of the assumed risk to safety to herself and those around her in the event of another episode? Any information/guidance is appreciated. – Anonymous, Pennsylvania