There is no evidence, anywhere, to suggest this could be MbP. I understand speculation, but this isn't always wise; an internet theory all too quickly becomes internet fact, and before you know it lives are ruined based on nothing more than a "what if".
Archie took his own life, that much we know. Whether it was a cry for help that went tragically unanswered or whether he really did mean business we don't know, but MbP doesn't fit the known circumstances by any stretch of the imagination. It just doesn't fit.
Sorry.