There is no letter 6475 for tax year 2022 since there were no federal stimulus checks issued for 2022. There is no place on a 2022 tax return to enter anything about stimulus checks.
As for your spouse.....he can still file a 2021 tax return. If you filed married filing separately for 2021 then your MFS return can be amended to a joint return and your spouse will need to enter his letter on that return. Spouse will put all of his information on the amended return.
https://ttlc.intuit.com/questions/1899507-how-do-i-amend-a-separate-return-to-married-filing-jointly
https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-return/amend-change-correct-return-a...
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**
