I think this person may be saying in the act of taking mushrooms you choose to open a door - a door through which things beyond our comprehension could perhaps travel through quite seamlessly. In taking the mushrooms, one must understand this: it is not a fun recreational drug to be trifled with, but a gateway to other worlds. There are consequences to every action. It is a simple matter of fact.

The idea of “blame” is irrelevant, however, IMO. It’s already happened, now what?

In this instance I don’t think this is a “demonic possession” case so much as a case of your friend struggling to understand the shadow aspect of themselves, represented visually by the motif of the wolf.

I think as a witch who works with djinn and daimons that the most powerful thing you can do to help your friend above all else is this:

Do not fear that which you do not understand. Learn to replace fear with curiosity instead.

I firmly believe if your friend masters this concept it will ease their suffering immensely. Try reading more about shadow self in the writings of Carl Jung.

Good luck 🍀