I don't think she actually asked him to "play;" I think they just accidentally ventured through the same portal at the same time and shared an adventure.
It was completely organic and spontaneous and amazing, and I should have filmed it, except I was worried that I would ruin it and make them self-conscious if I let on that I was watching.
They took turns being the customer and being behind the counter.
Based on how he paid, I suspect that at least one of the customers was a time traveler.
I didn't even know that she knew where I had tucked away the toy food and dishes.