I am a British citizen, and am going to be hosting a friend of mine who's travelling over from Brazil to the UK for ~3 weeks, for the entirety of his trip.
We've checked online, and it appears that they don't need a visa or anything like that, however the brazilian website says that border officers in the UK appear to ask for documents like "letters of invitation" for Brazilian people travelling to the UK?
Is this letter necessary? And if so, does it need to be notarised? Are there any other documents he'd need beside his passport?
Thanks!