Have him sign into his account from 2015 and go to his Tax Timeline, then click Load my Tax Timeline. Find the return you need information from and you should see Download to PDF file. Click on that and his return will download onto your computer so you can go back and get information from it.
If it still asks him to pay then you can go onto irs.gov and click on Get a Tax Transcript. They will ask you for some information. Requesting a transcript is free online.
