Mine were all over the place for 2020.  I would think there would at least be some expenses from Jan/Feb and maybe into Mar, 2020.  You may need to have your client check with the plan administrator to find out what the policy was for unused funds (the rules were relaxed at the federal level but it was up to each plan administrator as to whether or not the more flexible rules were adopted for the particular employer plan.)  The last one I finished (yesterday) had a reimbursement that exceeded the expenses because after the expenses were submitted the daycare closed and refunded everybody.  So the taxpayer got the money (pre-tax) out of the FSA as a reimbursement and again as a refund from the care provider.  So that excess was taxable, but there was also an amount that they were able to carry over to 2021 which we were able to enter in Part III on Line 14 (which means this mess will continue into 2021, ugh.)

Just one more fun thing to reconcile on the 2021 return!

Rick