Exactly my thoughts and I'd put money on it; and, it happens way too often. I do believe there's an element of alienation that is highlight by how this all went down. When the boys were officially announced by the RCMP as being "Missing Persons" … AS found out by seeing it splashed all over the front pages of the paper. This tells us that the simple gesture of letting "dad" know of his missing status prior to the names becoming public did not occur. The RCMP would not have released such prior to the NOK (Next of Kin) being told and that NOK did not request that AS be notified prior too.
In my line of work's experience with the Feds, NOK are given the ability to notify extended family members prior to the release of information on/names of an individual into the public domain by the RCMP, DND etc. Remember, at the time, these boys were just "missing" and not "wanted" which is a whole different ballgame. Whoever the NOK was, and I have my suspicions, did not exercise the ability to make the notification, or have the RCMP make the notification on their behalf, to AS prior to the public announcement. What a horrific thing to find out via a newspaper's front page.
And, IMO, it is clear by watching the interviews with AS that he truly loved his child, cared deeply and is heartbroken by all of this pain caused to the victims, their families and the impact in his own life through the loss of his son.
My heart breaks for the victims, their families and AS.