If he’d arrived at Frankfurt, the border cops would expect you to pass through their point in terminal one or two. So, if there is an entry....they have a computer entry that he came into the country. No entry....no record.
I live in the Frankfurt area and have used the airport at least forty times. It would be impossible to avoid the border entry control folks. The airport for the most part....shuts down by 11PM and they clear out folks inside for clean-up.
I would note too....that you have to pass the border entry folks first, before you get to the baggage area.
That is why we are so confused, there is video showing him getting onboard the plane but nothing after that, his bags arrived, but no sign of him.
Could you check the nearest hospitals to the airport?
Ralph Knight, white male, from Bridgton Maine USA
Thanks