perplexed175 wrote: What, if anything, can be done to help him?
First, what will not help this friend is incorrectly placing the blame for getting fired on exposure therapy.
If a friend teaches you how to use a gun and then later you end up shooting yourself, you don't blame the friend and you don't blame the gun. Sure, the argument exists that had the friend never introduced you to the gun that the accident would have never happened, but it is a weak, misguided, misplaced argument. YOU shot yourself. Take responsibility for your actions.
The same can be said for any number of things in life. You are introduced to gambling, alcohol, drugs, sex, etc. If only you had never been introduced to these things then your life would be different, right? It's a common, yet weak argument to deflect responsibility, to minimize the regret of your own actions.
So who or what is to blame for your friend getting fired and/or "shunned" by the community? Well, your friend is to blame, not the therapist.
perplexed175 wrote: He's now even more frustrated than he was before.
Frustrated? Why? He should feel liberated.
Once your friend takes responsibility, he can learn from the experience. And what should he learn? That opinions have consequences, and that's okay. What else should he learn? That many of his "friends" were not really friends. Good to find that out, no? And why work at a place that is hostile to your opinions? Great! It is wonderful not to be working at a place that did not appreciate his "good argument".
Had your friend kept quiet he would have never learned how his "friends" were not really his friends. He would have trudged along in silence, working for a boss that will fire someone for expressing a "good argument". Good thing your friend spoke up and was rewarded with all this hostility.
The only reason your friend is frustrated is that he values "fitting in" with fake friends and an intolerant boss more than the freedom to have and express his own opinions.
I recommend your friend use this experience as a fresh start. I recommend your friend continue to express his opinions and in doing so he will find new friends and a new job that better aligns with his values, beliefs, and opinions. I recommend he buy the therapist a gift for giving him the courage to express himself and discover the reality of his relationships.
Now, it is possible that your friend's opinions and/or "good argument" is morally and ethically appalling to most. For example, maybe your friend is a genocidal racist that believes in cannibalism. You did not provide details. But even if the "good argument" was morally/ethically appalling to the majority, there are still people out there and jobs available for those that hold minority views. It might be a smaller crowd and more difficult to navigate, but your friend is not alone.