From Cap 371:
10 Delayed Reporting Time in a Single FDP
10.1 When a crew member is informed of a delay to the reporting time due to a changed schedule, before leaving the place of rest, the FDP shall be calculated as follows. When the delay is less than 4 hours, the maximum FDP allowed shall be based on the original report time and the FDP shall start at the actual report time. Where the delay is 4 hours or more, the maximum FDP shall be based on the more limiting time band of the planned and the actual report time and the FDP starts 4 hours after the original report time.
10.2 When an operator informs a crew member before leaving the place of rest of a delay in reporting time of 10 hours or more ahead, and that crew member is not further disturbed by the operator until a mutually agreed hour, then that elapsed time is classed as a rest period. If, upon the resumption of duty, further delays occur, then the appropriate criteria in this paragraph and paragraph 10.1 above shall be applied to the re-arranged reporting time.
That's the law as it stands.
The problem in this case is that your friend didn't call the delay line; and we don't know when crewing were advised of the delay to departure.
As much as people moan about crewing, I don't envy them their job and have the utmost respect for them. Sure, some of them can be ratty and rude to us on the phone, but the way I hear some crew speaking to crewing on the phone it's no wonder. We moan about PAX taking out their frustration at the airline on us: we're doing the exact same thing when we have a go at crewing (most of the time).