I respectfully disagree with SaraEA. You should call the IRS and let them know what the situation is. They will probably take a look at his record and see if they have any open years on their books. They will tell you how many years they want you to file. I had two of these types of clients, one they wanted 10 years because they had open items that far back, in the other, they wanted 7 years because they had no earnings records at all for the client. After you get the IRS to tell you what you want, you can buy some time to get the returns prepared and filed. Then you can pull the transcripts and see what the IRS has for W2s and 1099s for the client.
Just filing the open years will get the refunds if there are any, but those other years are still open for audit because the statute does not start running until the return is filed. You need to protect your client from that audit exposure.
Still love you SaraEA, and I think you are very smart. I would just take a different approach to the situation.
Tom
Newark, CA