Filing 2019 Joint for my parents - Spouse passed 2020 - Any action on 2019 needed?

My parents file jointly.  I'm using TT for 2019.  My dad passed in 2020.  Is there anything on the 2019 that I need to watch out for?

 

And, is there something for 2020 I need to do to make sure my mom gets to add my dad's lifetime exemption to her's?  I think it's called "portability" perhaps?    Google search reveals: 

Portability must be irrevocably elected on a timely filed (including extensions) estate tax return, even if a return is not otherwise required to be filed.

 

Thannks in advance.