Absent an established employer policy providing a longer grace period, if this employee is on FMLA leave, you cannot terminate his health insurance benefits unless the premium payment is more than 30 days late, and you give him at least 15 days written notice that his coverage will terminate on a specified day if payment is not received. See 29 CFR § 825.212(a)(1).

Even if his health insurance is terminated because he failed to make premium payments, the FMLA requires you to reinstate the employee’s coverage when he returns to work as if he had never taken leave, or the premium payment(s) had not been missed. Equivalent health insurance benefits must be restored to the employee without exception upon his return from leave. The employee may not be required to meet any qualification requirements imposed by the health plan (such as a new preexisting condition waiting period), to pass a medical examination, or to wait for an open enrollment period to reinstate coverage. See 29 CFR § 825.212 (c).