"he thinks he's telling the truth"
I'm leaning towards this option.
As for the hearing itself: Testimonies, testimonies, charismatic preachings and heart-felt convictions galore..
0 actual evidence presented
Its all faith-based. "I believe this mans word! why would this Saint of a man lie? he's so respectable and honorable and integral and well trained etc. etc."
Sure, you most certainly can... its at the end of the day still an Ad Verecundiam, and doesn't prove squat
You could, in my opinion, replace the current witness on stance with an honest, respectable Cleric of the Ordo Exorcism and have him do a similar testimony on how he's really, really, really expelled a many demons throughout the years and that the Vatican is covering the "real" evidence of up so as to not cause world hysteria amongst the unbelievers.
And yeah, you could potentially, as a devout catholic or even as an Agnostic present in the room, be convinced of the man's honesty given his years of service and knowledge on the relevant subject.
however, this frysian heathen would like to see some actual evidence for fucking once after all this time, and no, by that I don't mean blurry pictures again, before I red-stamp anything as "truth"
looking forward to them actually pulling the alien bodies out of the morque and/or a working flying saucer out of the hangar for presentation and inspection
(not holding my breath though)