Chulent -“Hilchos Yichud are still in force when seeing a therapist.”
I don’t know if they are or not -I’m not a Poisek. And I doubt you are either.
But this would only be a problem if the client (woman) wasn’t married.
If the client or the therapist are women & are married and the husband is in the town – then there is no problem of Yichud.