I asked this in the main apologetics forum, but I don’t know if they will answer it so I will ask all of you good people as well.
I have a friend who at one time disagreed with Papal Infallibility, but believed in everything else catholic. He was ordained as a priest by an independent bishop who has apostoloic lines through the Duarte-Costa out of Brazil (Apostolic Catholic Church of Brazil). He has been a priest for several years
About a year ago, he finally saw the light about Papal Infallibility, and now teaches everything in line with the Roman Catholic Church. So now the question is, if he kept celebrating Mass, would Roman Catholics be allowed to go, or does he have to join a diocese? If he must join a diocese or religious order, what would be involved with that, and finally, would the Roman Catholic church allow him to keep performing his duties as a priest?