That doesn't rule out anything. Max may well believe his father did his mother in. And, he may have. What we know for sure is that Max didn't "get closure with his mom" because he wasn't allowed to go to her funeral or to visit her while she was dying.
HLA and his father stole his youth, something he'll never get back. Like his mom.
Did his mom ever come to HLA? Was she in favor of his placement, or was John the sole driver of the process? What was his mom's cause of death?