This is a third party quote. Here is the quote:
"Padre Pio said that Martin Luther is in Hell and Christians today who follow him will meet the same end."
It is attributed to Fr. Stefano Manelli, founder of Franciscans of the Immaculate, who knew Padre Pio. Now I am not saying that this Fr. lied however, this quote is a matter of opinion not revelation if true. There was no vision.
It is a matter of opinion only. You are correct. But even if there was a vision it would only be private revelation and we are not compelled to believe that.
Additionally, it does not make sense to claim the final destination for anyone. Catholicism teaches there is a purgatory prior to final damnation. Clearly a saint would be praying for everyone to come out of purgatory and go to heaven! And, not proclaim hell on those who are not Catholic. Let us reason!
Purgatory is a place or state of cleaning up for those already saved. You don't even get to go to purgatory if you're damned. Everyone in purgatory ends up in heaven. We can pray for them, but it is not a prayer to save them. Already saved. OTOH when we pray for the damned it is because we don't know if they are saved or damned but we do what we can with our limited knowledge, so we pray for them. So we pray. God does His just and merciful thing. We find out later on.
( Coming from one raised Catholic, me)
Be blessed.
Many people do return to the Catholic faith. Al Kresta who recently died did that. He was raised Catholic, went off into New Age stuff, became a Christian, and a Protestant pastor even, with a radio show in Michigan. One day he interviewed a Catholic priest and he realized that priest had answers to questions that were bugging him. He was a premier apologist and founded Ave Maria Radio, which has it's many programs picked up by EWTN.
The Bible timeline guy, Jeff Cavins had a similar story. Raised Catholic, Protestant pastor, had questions, and ended up Catholic again. His Bible timeline has been helpful for millions of Catholics, helping to make sense of the Bible and not get lost in the OT.
Lots of other people in the same boat. For some reason being Catholic didn't grab them early on. They came to an adult faith as a Protestant, and some even excelled in Christian service and learning as Protestants. But not everything sat well, and their questions finally made sense with Catholic answers that compelled them to give a new look at being Catholic.
I noted that your answer about purgatory wasn't quite right. Close though, which only counts in hand grenades and horseshoes. Perhaps you need another look at what Catholic teaching really is. Perhaps you have questions that you can find answers to in Catholic teaching. Let us know if we can help.