He had enough clarity to pull over and put hazards on, he came round when the police got there, blanked out again then came around in hospitalIf following his blackout he's seen a GP or a consultant, he'll have been told that he's obliged to inform the DVLA, an automatic 6 month medical driving ban will follow and he'll be asked to surrender his licence. The cause of his blackout and the treatment he receives will be reflected in how soon he can reapply for his licence.