BEFORE grandpa dies, someone else needs to join cougar club and be prepared to buy tickets.
The original seat holder (grandpa) should not do anything with tickets when renewal time comes. End zone seats only go away after renewal purchase period.
When the new persons time comes, the original person (or proxy) logs in and release their seats. The new person should then scoop them up.
I did that when my grandpa was close to dying. Still have our tickets.
Or a modification would be to take a few seats and not all depending on who wants them in their name.