[L.J.Steele]

Is he a cat person -- if yes, Magical Kitties Save the Day. Completed its Kickstarter and in progress to publishing. You can likely get the kickstarter release rules in pdf.

Secret Lives of Gingerbread Men -- snack and game. Animated Gingerbread cookies (why limit yourselves to people -- I have cookie cutouts for animals, Godzilla, etc.) have one night (Christmas Eve) to accomplish a goal (defined by the player). Beware the Hungry Dog! The cookies have powers based on the candies used to decorate them -- use a power, eat the candy. Take damage, eat a limb. I had worked up an adventure verse the Gingerdead men (gingerbread men with icing skeletons) and their master, the NECCOmancer.

Adapt Scoobie Doo or Ghostbusters (note that Playmobil has sets for both) to Fate Accelerated -- easy mechanics to remember and use -- to the extent one needs them.

Its not an RPG, but Happy Birthday, Robot! can be a lot of fun once the young'un can read reasonably well. Cooperative story-creating/improv. For that matter, Once Upon A Time is good for semi-cooperative story telling.