It is fairly clear that the Apostle John was the younger brother of James and probably only about 12-14 years of age at the start of Jesus’ ministry. This is why Jesus spent valuable time instructing him, since John would have not needed to relearn unwarranted beliefs, like the other disciples, such as the concept of wealth indicating righteousness. John, being a young teenager in 30 CE could have easily lived to 90-95 CE when his gospel and Revelation were written. After reading the many different theories of authorship of Revelation, I firmly believe it was John the Disciple and brother of James, sons of Zebedee.
By the way, Paul’s epistle, which we call “Ephesus,” really has to be “to Laodicea.” Many writers, good and bad, have recognized this fact. The “to Ephesus” is probably a later addition from a scribe who found the copy in this city. Paul (and the Spirit) wanted the Christians to compare different perspectives, both true, in the letters of Colossians and Laodicea. This is the only way for Col. 4.16 to be fulfilled. Paul instructed both of these letters to become circular, and therefore copies were commissioned to accomplish this command. The city of Ephesus, scarcely 100 miles to the west by way of a prominent trade route, would have been a natural repository for one of these copies, years later, and, would have served subsequent generations who didn’t know Paul, personally, like those among whom he ministered. Because Paul spent nearly three years in Ephesus that church didn’t need a correspondence the way that Laodicea and Colossians did. Paul only “heard about their faith” (Col. 1.4, Eph. 1.15). The absence of any personal greeting in Ephesians is, too, out of character for Paul who spent the bulk of his ministry in this city.