You are taking on a major task for this person. Kudos to you for doing this. I would go ahead and file them. The only way to file them is by mail, so the sooner the better to get them into the system. Then go ahead and prepare and e-file 2020 and see what the IRS does. Even if there is a delay---your relative is no worse off than if you do not file them.
**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.**
