How exactly does "what" work? And what do you mean, exactly be "reprobate?"
And why are you so quick to bring up the topic of pedophie priests? Your question really has nothing to do, in general, with "pedophile" priests any more than it has to do with a priest who drinks too much or gambles too much or skims some money, or loses his temper, or swears, or gets impatient with the demands of his office.
All is sin, right? All makes us unworthy?
So, without being combatitive and attempting to denegrate others, you could have just asked how a sinful man can be used as a vessel for Christ.
But you didn't.
SD
I can answer that one, "It can't" be, .you said so a hunnert times, that God would never enter into an unclean vessel as in Mary's case, so a pedophile priest can not be used as a vessel of Christ or the Holy Spirit.
Thanks SD, that was easy thanks to you.
JH, taught at the Vatican :-)