That does not support the roman catholic view of mortal sins. It supports the Roman Empires position on capital punishment.
How does Jesus actions support the Roman Empire?
Again the good thief asked to be remembered (baptism) and be part of Kingdom of Jesus. He spoke out and stood up for Jesus (action - works). He confessed he sins and accepted his punishment.
Again, not everything in written in the Bible, Catholics follow tradition as we were commanded by God.
It is clear that the oral teaching of Christ would last until the end of time. “’But the word of the Lord abides for ever.’ That word is the good news which was preached to you” (1 Pet. 1:25). Note that the word has been “preached”—that is, communicated orally. This would endure. It would not be supplanted by a written record like the Bible (supplemented, yes, but not supplanted), and would continue to have its own authority.
Then he said, “Jesus, remember me when you come into your kingdom.”w 43He replied to him, “Amen, I say to you, today you will be with me in Paradise.”