At this point a person must use prudent judgement for the best to “correct” this person. Either by using frank speech to shock them out of their imaginings by letting them know they are in jeopardy of having their friends lose faith in their ability to perceive reality or simply to leave the person to their imaginings neither reinforcing them but also never speaking of them again. I guess it depends on the relationship a person has with the other.
So i gather that this person is in a circle of relationship where it is appropriate to try to correct them, as opposed to simply separating from them?
This particular person believes she sees “things” like angels, spirits, demons etc.
That's a pretty specific list. So you do mean this literally, that this person says she actually sees these things in front of her, or is it still at all possible that she is talking figuratively?
I would almost be tempted to think it is possible that this person thinks that they are "ministering" to you by insisting on something that she really doesn't believe herself, out of a desire to try to bring you back into the fold.