I am Delta platinum (had few flights on business class for work last year) and have 4 SWU certificate expiring in Nov.

My Mom would be flying from Mumbai, India to Phx, arizona in early Aug and would like to use the SWU certificate to upgrade her. Her return date would be in 1st week of Feb.

I have 184K miles but don't mind paying for the ticket and upgrade using SWU. Which class ticket should I search for to use the SWU certificate for upgrading international segment to business class (From Bom to Europe and Europe to US).

Even though my upgrade certificate expires in Nov, can I use them now to upgrade her for the return travel which would be in Feb.

Appreciate any input from the experts.