If the "son" has been driving for any length of time he will have seen that ALL motorway services have notices advising that parking charges will be levied if a vehicle is parked for more than 2 hours. They also display notices stating that it is illegal to sleep overnight in their car parks. Since most m/way services have a cheap hotel attached to them why not book in a get a proper sleep?
I shan't go into the rest of the nonsense posted in that thread but most of the so-called advise is bollox.