I don't think that exact shirt from the brain treatment foundation is for sale. I think it was a giveaway.
https://www.foxnews.com/opinion/paul-ba ... cial-media
https://braintreatmentfoundation.com
But there are tons of places to buy shirts with similar images on the chest.
https://www.google.com/search?q=chris+p ... e&ie=UTF-8
ETA: Made in Austin TX. Amazon LINK