By banning 8yr old boy and his father from travelling

Now bear in mind this is a Daily Mail story so it's unlikely the whole truth is present.

So what do you think the real story is?

Father is banned - but not the mother - so why is the child banned
Child didn't have an ESTA - but how did they check in
Father has a very sick friend who thought it would be a good joke
Child is indeed a terrorist threat to the US.

BUT since when does the US have DHS operatives on the ground in the UK?