Hi Patricia,
How fantastic that you have tickets from 1998! I feel sure I would have put them somewhere safe and promptly forgotten where they were! You can try to call the phone number for help with existing tickets, (407) 939- 7523. They might be able to help you confirm how many admissions you have left on your tickets. I also found
this answer in the "Help" section of the Walt Disney World web site:
"Q. How can I determine the number of days remaining on a theme park ticket?
A. When you arrive at Walt Disney World Resort, please show your ticket to a Cast Member at any of the following locations:
Ticket windows at theme parks and water parks
Concierge desks at Disney Resort hotels
Guest Relations at the Downtown Disney Area
If you wish to check from home, please email us at ticket.usage@disneyworld.com and include the following:
Photograph or scan of the front and back of each ticket
Photograph or scan of a government-issued ID
Your full name
Phone number where you can be reached during the day
Please keep the total email size, including attachments, below 2 MB. To ensure your email is less than 2 MB, you may need to compress your images or send multiple emails.
We’ll try to get back to you as soon as possible, but it normally takes 14 business days for a response."
To exchange your son's child's ticket for an adult ticket you will need to visit one of the locations listed above.
Thanks for stopping by the Disney Parks Moms Panel. Be sure to let us know if we can help you with any other questions!
Wishing you happy planning and a magical vacation,
Amy H