Dealing with Another's Passive-Aggression

Good question. The short answer is "gingerly."

A somewhat longer answer is to deal with the person in a straightforward but non-attacking, non-accusing fashion. P-A's are likely to get very defensive very quickly, and then they won't be listening to you at all but preparing their rebuttal and defending their innocence.

You need to describe to them your own frustrations without also communicating that you see them as intending to hurt you or take advantage of you. Offer feedback, not criticism. And try, even as you're pointing out to them what in their behavior troubles you, to be as empathic toward them as possible (not an easy task). If you try to see things sympathetically from their viewpoint, then (unless they're too "far gone") they may be willing to listen to your own and begin to confront themselves (rather than you).

But try not to set your expectations too high . . . and let me know what happens.