Because both UK and Thailand drives on the wrong side of the road, then it makes more sense... The rest of us Europeans, our cars only gets to Lithuania.
I would not touch it (anywhere).
The few times I have been food poisoned outside Asia, has twice been due to raw beef.
One of these times completely knocked me out.
You have to go by your own experience, how sensitive stomach do you have, etc
Still no excuse.
I hope he'll be happy to pick up the tab for the diversion.
Diversion costs typically range from £10,000 - £80,000 depending on the size of the aircraft and where it diverts to.