Andre Tabayoyan was always a very honest person, too. Unlike others, his loyalty was first and foremost to L Ron for personal reasons, not to Scientology. He did everything he could to expose what happened and the coverups of L Ron's death because he was his friend.
Their relationship and Andre's loyalty had nothing to do with belief in Scn. Afterward, the DM administration took the Tabayoyan's dearly loved son, Cassavius, away from them - with name change and all - causing the Tabayoyans unbelievable heartbreak.