Is he a targeted individual, which would complicate keeping him free of trouble? Or is there a large karmic liability to spirit involvement that will complicate restoring him?

This is not the case, that he is in a high-risk category from being targeted or that this is a deep karmic issue as much as opportunistic spirit manipulation having gained the upper hand, as happened. So this should be a straightforward exercise to liberate him from this torment and give him his life back.