In a movie his mental health issues would likely have been caused intentionally by the attacker, setting the stage for the mole to offer to step in just at the right time. Seems a bit far fetched in this case though for what looks like a tangential attack.
Does it? I expect that finding someone vulnerable was the more likely approach rather than messing with the life of a stable maintainer, but it does seem very much like the attacker was acting with malicious intent from the start of his interaction with the xz project.