Pasting this from a previous post I made last year:
Purchase the Happy or Energized Potion as a reward. Have your elder drink the potion. They will be very Happy or Energized. Then have them go jogging. They will jog until they get the Dangerously Tired moodlet - but this moodlet will be overridden by the Very Happy or Energized moodlet. Then have your elder go jogging again... and have them meet Grim.
Note they need to drink the potion before going jogging the first time, otherwise, the Dangerously Tired moodlet will stick to the front and override any other positive moodlets, even if they drink the Happy potion afterwards.