According to TW in their 12/23/20 media interview, he said JW was inside the home wrapping Christmas presents and they thought it was a good idea to have the boys go outside so they wouldn’t see the gifts (paraphrased). I would assume if she were wrapping gifts behind closed door in the house, no reason for 2 little boys to be sent out into the cold night since TW would be able to watch them inside to make sure they didn’t disturb her while wrapping presents, so IMO, JW would have seen the boys come in from the outside.
Also iirc. they had those double slider type doors leading to the back patio. I have those type of doors going out to my back deck, they are very heavy and the latch to open and close is way above their heads/out of reach of my 3 & almost 5 year old Grandchildren. They need lots of assistance opening and closing when going in and out those doors.
At any rate, JW apparently knew they weren’t in the house as TW said when he went back inside after realizing the boys were gone and that he’d left the back gate open, he said he went back inside, asked my wife, you seen the boys, she says no they’re outside playing with Chalk, and said he went right back outside started searching.
JW knew those boys weren’t in the house, IMO.