From your link:
His mom told WTOL 11 Sunday night that Braylen last was seen in his bedroom. She was in the back balcony and his grandmother was in the living room.
There was a window open, so the assumption is he fell out the window because the screen was pushed in but his mom didn’t see actually fall.
...
Cox clarified she can't be sure that Braylen fell out of the window, but based on where Braylen and Braylen's grandmother were in the apartment at the time, and because she saw the window the screen was pushed out, she can't think of any other possibility.
She said there's no way Braylen could have snuck past both her and Braylen's grandmother, as both were in the apartment at the time.
Toledo Police seek missing 3-year-old child Braylen Noble | wtol.com
If this story is true then the timeline possibly changes. The original story had her immediately running down and outside to get him after he fell. But if she's now unsure if he even went out the window then Braylen could have left the apartment at any time. IOW he could have been gone for quite a while before the mother noticed.
I have trouble with this version too. MOO.