Some additional info, from the original newspaper article; FWIW.
He was rostered for 5 inter Scandinavian stretches, this happened on stretch 4.
When the doorbell woke him up, he was momentarily disoriented and could not immediately locate the door opener, being newish on the 737.
SAS chief Pilot Bjørn Granviken confirms this has happened last summer. The pilot is anonymous, and the report is intended for use by SAS pilots, not the newspapers.
SAS pilot union foreman Jens Lippestad mentions that pilots have a duty to inform the company when they are too tired to fly. He says current flight time regulations are too flexible and can too easily cause pilot fatigue.
- The rules are too parsimonious - says Lippestad.
Again, this is from a newspaper report; uncertain veracity.