I have a relative that was very close to the entire family and we have discussed this situation as nauseum. I feel I can offer some insight based on this second-hand information.
Secondly, it is my understand that P & A are NOT drug addicts. While there may have been some substance issues in the family, those two did not give people close to them a reason to believe that there was anything more than occasional marijuana use by P. A did have a valid, legal prescription, which I believe is what LE found. It's worthwhile to take note that NO drug possession charges were filed against them, despite it being reported that prescription medications and a small amount of marijuana were found in the home.
It is also my understanding that the parents were actually very selective about who their children spent time with. While it is obvious that they excercised horribly poor judgement in leaving two young children unattended, it is my belief, based upon the personal information shared with me, that it was likely that they THOUGHT the children would be better left sleeping than to be woken and taken on the morning work trip. While I do not know if Noah was also suffering from the same cold, it seems reasonable to me that he was either coming down with, actively, or getting over the same cold or flu as the baby had. It also seems reasonable to think A may have also been under the weather, which could very well explain a 3 hour nap in the morning, if in fact that nap did occur!!!!
While I cannot claim to know what happened, I can say that there are people within circle of family / friends that are responsible, reasonable, sensible, and clear headed that can not imagine any situation where these parents either harmed their children or played any role of placing Noah in that tank.
Yes, I am aware of the charges and have read the code over and over and have read all sorts of other people's interpretations and ideas of the code. I know that these parents were absolutely neglectful in leaving their children at home, unattended and that they are being charged with felonies because of it. I also know that people can be deceiving and can surprise even their closest friends and family members. I realize that it is possible that what went on in their home could be very different than what they portrayed. However, that being said, I am close with my relative also and as such, I feel that this was a horrible, tragic accident. I do not believe that Noah's parents had any knowledge of him being in that tank beyond it being a place worth searching since they couldn't find their child and it was seemingly a known hazard.