Client came to session high

Okay, I know it sounds terrible but I have a client who has severe anxiety. Right now she is waiting for med management services so she is not on any kind of medication. We have engaged in a lot of skills and she finds they are not great at reducing her anxiety. What works, however, is if she smokes (takes a hit of her weed pen lol). She disclosed to me she took a hit right before our session and her anxiety levels went down. Is this absolutely terrible to allow or is it okay? I don't think I would want any other client to do it if they were just smoking for fun but she has severe anxiety and nothing else is working right now. She was able to engage in session and be present.

EDIT- i see her via telehealth