I haven't listened to this, but here's an interview of Fr(?) Dr Coomaraswamy on Art Bell, specifically regarding his relationship with Fr. Martin, that sounds like it might be interesting.
Welp ... within the first few minutes we have a direct contradiction.
Fr(?) Coomaraswamy says that Fr. Martin told him the story of how he read the Third Secret. He said he was riding in a car with "Pope" [sic] John XXIII when Roncalli just out of nowhere apparently handed him the Third Secret and made him swear never to reveal it.
But now we have this Marro guy relating an entirely different story, where it was Bea that gave him the Third Secret to read after leaving a meeting where he could overhear some shouting and yelling, and then Bea swore him to secrecy.
So ... which one was it?
Either Fr(?) Coomaraswamy was lying (I'd say not, as he would have better character than to do this ... and he could make up all kinds of stuff if he wanted to, to spice it up, and yet his stories about Fr. Martin are pretty ho-hum), or else Marro is making it up (to sell a book) or else Fr. Martin was lying, having in fact related both stories but unable to keep the lies straight.