Is he waiting for a refund? See the first question at IRS
https://www.irs.gov/newsroom/irs-operations-during-covid-19-mission-critical-functions-continue
"The IRS is now opening mail within normal timeframes. The IRS has also made significant progress in processing prior year returns. As of May 15, 2021, we had 300,000 individual tax returns received prior to 2021 in the processing pipeline. Including current year returns, as of May 15, 2021, we had 16.4 million unprocessed individual returns in the pipeline........"
