Apparently, you can't.
My 95-year-old grandmother went south to see her sister when her sister turned 100. She went with my inactive aunt and uncle and my non-JW aunt and uncle. No presents, no speeches, just dinner and time together. My grandmother has pioneered for over 40 years, her health and memory are just starting to deteriorate, and she hadn't seen her sister in a long while.
When she got back, my elder father (her son) made sure to call her and lay her out for going to a birthday party. Had to get her good and upset to teach her a lesson. Ironic that she turned to my inactive aunt and uncle for comfort afterward.