Hi there, Manuel!
Welcome to the Disney Parks Moms Panel. First I'd like to thank your grandfather for his service to our country. It sounds like you are referring to your grandfather purchasing the
3-Day or 4-Day promotional ticket offer for members of the U.S. military. These exclusive tickets can be purchased at a military base by an active or retired service member with military ID. If your grandfather purchases these tickets with his ID, he will need to be present at the gate on the first day you enter the parks. He also will need to be one of the people using the tickets with you. After your very first park admission, he will not need to be present with you as you park hop for the remainder of the ticket. The rules regarding these tickets are very strict, so I'm glad you asked before heading to the parks! If he chooses to purchase you
standard Disneyland Resort park tickets then he does not need to be with you to enter.
If your grandfather joins you, I hope you also look into some of the wonderful military benefits offered on rates at each of the three
Disneyland Resort Hotels. To access these limited discounted rates, you will need to reserve your room by phone by calling (714) 520-5050. Keep in mind your grandfather will need to be present at check-in with valid military ID.
I hope this helps, and have fun making memories at the Happiest Place on Earth!
-Jennifer