Hi, I am not defending your friend in any way, but to the people who critisize this proble of sleeping whilst driving.
I had been driving for 38+ years on all types of HGVs as drivers of these things you get used to going long distances but can assure you it is common to do this, I used to travel from Lancs to Glasgow near every night & back within my hrs & break times there were many times when you were driving that you did not know where you where! ( you think i'm jokeing?) belive me Im not there were times on the motorway when the studs between the inside lane & hard shoulder had woken me up, you may think this impossible, If there are truthfull HGVs on the site wait for their honest replies. so before you start calling people for this problem think before you write (It may happen to you)