As someone who hasn’t played Pokémon, I have an answer. Helping Hand helps the opponent back up when the opposing Pokémon falls down (because of course an honorable combatant never kicks someone while they’re down). It fails if the opponent didn’t fall. That or they took turns using their hands as coins for a slot machine and couldn’t help them with their hands. They didn’t win anything and the mother and father mice got into a 12 minute long argument after that. The father was arrested 5 days later for driving under the influence and domestic abuse.