Fulton Sheen had a humility all too rare in these latest generations. A true man of God.
The deal on sainthood is that the miracle occurs by praying to the deceased saint. Saint does not perform the miracle while alive but after death intercedes on behalf of the afflicted.
Your not being Catholic, it’s understandable the confusion or seeming downright absurdity of a man performing a miracle.
Asking the dead man for prayers, assuming he is in heaven, to Jesus to perform the miracle....we pray to a dead guy to keep praying to jesus while we are unable to....i.e. Constantly knocking...
If he is in heaven, Jesus hears him well not as a sinner like me but certainly knows he who he let in.
We pray for Mary to pray or intercede for us too as she was sinless.
We pray to our dead parents similarly.
We pray that dead people are accepted iby Jesus as well. Only God does miracles but sometimes through living or in the honor of dead people so we can see they are with Him.
All that goes into the recognition of a saint.
No Catholic believes that Sheen or any other saint "performs miracles". "Intercession" by a saint means that a petitioner asks said saint to request of God that a miracle be granted.
Why stop at sainthood? Anyone performing miracles is God, right?