Take it to a bank and have them verify its validity.
Be aware, if real and you weren’t due the check, they could come back for it sometime in the future. (Ask the banker)
It could also be the result of someone stealing your identity. You should consider running a credit check on both you and your wife
Nevermind. I missed your post comment.
Looks like you got it figured.
Grats
But that would remove all the mystery.
/s
That makes no sense. The IRS told him the reason for the check. And why would someone steal his identity in order to cause the IRS to send him money?