I don’t know who your source material was, but they are completely off. Not only did Martin work directly in the Vatican himself with direct access to two popes, he had many direct sources. He not only performed hundreds of exorcisms himself, he knew of thousands of other cases through his priest network. Moreover, he was highly sought out by those victims and families who needed the service. His book, Windswept House was “faction.“ It was real characters with different names describing real events. You don’t take on the corrupt Vatican and not have an army of critics descend upon you.
A priest stripped of his faculties CANNOT exorcisms. Period, end of story. Martin's career as a priest ended in Rome during Vatican II, when, among other things, he fled the Jesuits after he was found to be in an adulterous relationship with the wife of a Time Magazine correspondent. That he was defrocked in the late 60s is without question.
He also, at that time, wrote secretly under a pen name for the American Jewish Committee and other periodicals promoting VII. He was a leftist who disgraced himself who made up a lot of crap about himself and others to sell books.
Not to dis you, but objectively speaking you obviously have very little knowledge of the man, and you don't know what a real exorcist is.
Do your homework on the man - his "works" are nothing but pure trash.