The Family and Medical Leave Act (FMLA) does allow employers to require appropriate documentation to support a leave request, as well as periodic reports on the employee's status and intent to return to work.
Questioning the staffer's honesty could be interpreted as retaliation, which is prohibited. Concerns about the leave should be directed to HR, not the employee.
The FMLA provides that covered employers must grant an eligible staffer up to a total of 12 work weeks in any given 12-month ...