I think we've heard enough about the Youth to know that he could have killed Logan himself at any point in time with no help from JC. MOO.
Martial arts kicks to the stomach and groin? Knocking him over using 'sweep' moves? Tripping / throwing him down the stairs?
I think it's quite fair to say that JC could have left the country and Logan's life still would have been at utmost threat. And equally / more so that of the baby as a baby can die instantly from any small incident. Their lives were at immediate risk both from the Youth and from the mother's habit of knock out sleeping. Add JC into the mix and they didn't stand a chance. I would suggest AW's life was also at utmost risk.
Personally, I'm not buying into any narrative that the baby was 'safe' due to being JC's flesh and blood. The baby was not safe from it's own mother by dint of the fact she took knock out medication at nights that she testifies she cannot be roused from. In and of itself, that makes her a clear and present danger to her own baby and own 5 year old. Bear in mind that JC and the Youth did not live full time together with AW, Logan, and the baby - so on nights when she was their sole care taker, she was effectively abandoning them by knocking herself out. Anything could have happened. If she'd left the house and gone out, that would be a crime, but she did the same thing whilst in the house!
Also when they were all together at JC's home they were in a house with stairs and a violent, unmanageable youth. At any time something very serious indeed could have happened. It is being implied the Youth has some kind of cognitive issue, low IQ, or learning disability in addition to being uncontrollably violent. I doubt even an adult was safe from him, hence why JC got awarded him in the first place.
Nobody in that house was safe - in ranking of 'safest' would be JC at the top, the Youth second top, and AW third.
In ranking of most unsafe - a baby is always the highest risk, then Logan, then AW, then JC and the Youth joint bottom and I think either one of them was so deranged they could have killed one another on purpose or misadventure at some point.
We've heard no mention of weapons being used, or makeshift weaponry, or things like fire starting. But all those types of things exist within the remit of disturbed, violent, teens and adults.
AW must be held to account for this as she will be doubtless fighting for her baby back. And UK Social Services being the pathetic thing they are will be fighting for her to.