Maccabees is the Scripture from which the Catholic teaching of Purgatory arises. 2 Maccabees to be more precise. At the time of Jesus Maccabees and some other books of the Old Testament were considered part of the Scriptures.
No where in the New Testament does it state that these Books should not be considered part of the Canon. Therefore I include them in Scripture. Well after the establishment of Christianity in Rome Jewish leaders removed these books from the Canon of Jewish Scripture. After the Reformation Protestant leaders did the same.
CS Lewis believed in Purgatory and so do I. It does change your perspective on the question of salvation. Jesus is still the only way to Heaven but people get a “second chance” at salvation through Purgatory. This isn’t exactly Catholic teaching on Purgatory but it does align with CS Lewis ideas presented in “The Great Divorce.”