The Thessalonians were a young church and yet Paul was teaching them about prophecy…a forth telling of things to come. We have a complete record of that as the Bible now, but in 52-53 AD they did not.
Paul reassured them that their loved ones had not missed the Rapture in IThessalonians. In II Tessalonians Paul shares that those who persecuted them would receive His judgment. Two separate people groups and two separate events.
Does that clear things up in your understanding of the Word, or does it complicate matters?
Are you doing your own study to show yourself approved of God? If so, please share your insights into God’s Word.