When someone is running themselves into trouble, by needlessly fucking with other living beings, you can often influence them by contacting their Higher Self.
This is the part of them which exists permanently on the spiritual planes and carries awareness of all their former lives, and will be aware of the ramifications of actions they’re currently taking.
It’s a concept used a lot in core shamanism, and I have found working with people’s HS’s, when done for their own benefit, to be effective and powerful.
This situation seems to be a good candidate for that, using the worldview that comes with core shamanism.
I’ll paste below a method I posted for influencing a HS, which you can adapt to your needs, PM me if you have any questions about it:
That merges the core shamanic concept with spiritual evocation, you can also soul-travel to someone’s HS, using shamanic journeying.