Hi Elizabeth,
I am tinkled pink to hear that your 99 year old Grandfather is going to WDW! How cool is that?! Be sure to stop by Guest Relations and pick up an "I'm Celebrating" button for him because this will be a trip worth celebrating.
There are indeed assistive devices available that can help your Grandfather. Assistive listening systems utilize a handheld device that receives a signal in order to amplify sound through headphones. Handheld Captioning devices are portable and use a wireless handheld receiver to display text in locations on moving attractions. Please note that not all parts of an attraction may be captured. Both of these devices are available from Guest Relations and require a $100 refundable deposit (subject to change). The device must be returned on the same day for a refund.
Another option is Reflective Captioning that is available at many of the theatre-type attractions. These devices utilize an LED display to project captions onto a panel positioned in front of a Guest. To utilize this option, see a host or hostess at the attraction.
Click
here for the link to hearing disabilities section on the WDW website for information for which attractions, restaurants and entertainment locations throughout each of the theme parks work with each of these devices.
I'm so excited for your family's upcoming trip. Wishing you many magical memories :-)