So i recently lost one parent. Surviving parent discovered that taxes have not been filed since 2017.

All the W2's and or relevant paperwork seem to be there, just, never had anything done with them.

How do i help my parent get this taken care of? It sucks, there isnt really savings to speak of but it has to get taken care of regardless of where it ends up. Plus there is a chance that they dont really owe much anyway, might have even had refunds due? Taxes were withheld from paychecks, all that, just again, nothing was filed with state or federal. We assume there might be penalties and interest, it is what it is at this point.

Thanks in advance for any help.

Edit: It seems the best thing to do is file by mail for years 2019 and 2020 and then get last years filed as normal (although late) for 2021. Expect delays due to backlogs but overall easy enough to get done as their taxes are very basic.