In a case like this, you just buy the tickets for your grandfather and print them out for him.

If the app is meant to defeat counterfeits or reselling the Dodgers won’t be willing to accept printed tickets.

It's not possible to make counterfeits with a modern ticketing system. Each ticket is a unique code, and they are scanned on entry to match with the codes in the system.

As for resale: The attendee name is tied to the ticket in these cases, and ID is checked at the door. I guess an app could be more effective for preventing this than normal digital/paper tickets.