... turns away from the home after allegedly arriving at the home.
I’m thinking that violates Occam’s Razor.
Not if he counted on the kid being in and awake when he returned, leaving for the store without a key, and then the kid falling asleep or whatever when he returned and not answering the door. The drink and skittles was imho probably not for the kid, so it would not be as if the kid was eagerly waiting for M to return. Sometimes children misunderstand each other or forget about each other or deliberately ignore each other. It might not happen often but I do not think it is uncommon. I think it would be more uncommon for M to reach home in the dark and rain, get inside, and then go out again.