He's an atheist psychiatrist. However, he enjoys how natural selection, social dynamics and reputation can also be modeled by the moral rules of most religions. For example, going to therapy isn't that different from practicing confessions in a church.
Depends on the kind of therapy. Some are more dogmatic and one might even call them "religious" (overloading the word), while other forms of therapy are more grounded and based on empiricism -- the latter ones are far removed from religious confession.
If your therapist responds to your sharing by suggesting that straying from their advice, or some kooky ancient text, results in eternal damnation then run far away. Churches can be devastating to ones mental health. Do not recommend.
No issue with your first clause: indeed, churches can be devastating to one's mental health (as can ~anything). That observation does not support your second clause. Religiosity is generally associated with lower mental health problems [0]. Correlation is not causation, of course; difficult to do a prospective study in this field.
[0] E.g., https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8462234/