I'm not quite sure why some are stating that the father turned himself in to LE and confessed. I have not read that he has confessed to anything other than being present when Sherin "choked" on the milk and quit breathing. He has only admitted that he "assisted" her in drinking the milk. Careful wording on his part, IMO. He is insinuating that her death was accidental.
Personally I don't think that he had a case of feeling guilt. I think he feels that what happened to Sherin wasn't his fault at all but her own fault for not "listening" to him and drinking her milk as ordered. I think he is a man who has to be in control of everything, including controlling when he goes to the police department. He decides when to go in, not LE making the decision on when to bring him in.
I also think that the mother is doing exactly what he instructed her to do ie., keep her mouth shut and just say she was sleeping.
Just my opinion here.
I think in the majority of cases that you'd probably be right on the mark. But often when one thing happens 95% of the time and another only 5% or less, then our brains are programmed to give the majority-time explanation. I think it's a human thing and it takes a complement of multi-disciplinary LE examination to turn up the minority-time explanation, as even then the public might find it really hard to believe.
For this reason I think we should always be careful of assumptions, even about the observations of our own eyes and brains, because we can be confused by things that have happened in our past, in our experience, that every time we've read, seen, experienced something that there was one reason, so we extrapolate that it must be the same reason this time, and we actually end up interpreting what we see and hear through that narrative that we expect to be the explanation.
That's why it's so important to have the evidence in court given and not just a confession, not just an eyewitness report, but to also have psychologist analysis, to do statement analysis, etc.
When I read the report that WM said "she wouldn't listen to me" I took note of the word "me" at the end in the thought that it was self-incriminating despite a lot of other aspects of the stories sounding more generalistic. And I think there could be multiple reasons for the more generalistic tone, it could be blaming the victim, it could be an attempt to make a cover story that changes grammatical use.
And, though I don't know a lot about statement analysis it's something I am currently very curious about, and I am concerned at that discipline at some of the conclusions I see being drawn, because some turns of phrase can be dialectical, they can come down to someone not having English as their first language, and conclusions risk coming from a majority-case conclusion...which is why they work through every single word and sentence and not just one single thing and they can still really (imo) only say that there's 7/10 things in this statement that imply something is being hidden and you should look in a particular area for that hidden thing but they can't say for certain what that hidden thing actually is.
The human brain is wired to see a dead body with someone standing over it with a smoking gun and voila: we know what happened and who the killer is. Ninety-nine times out of a hundred we'd be right. But not every time.
I have enjoyed and appreciated your insights. 
