Thanks for the replies, everyone. Based upon your feedback and further investigation, he decided not to risk it and re-booked. He's traveling next week, so the procedure for the Air Asia flight might not yet be in place. That flight allocates 1 hour 15 minutes for transit, and passengers must go through security re-screening but not immigration.

He discovered that he might also have faced an issue whereby his self-printed boarding pass might not have registered as having cleared local OOL security. I know this happens at other airports, such as in Beijing, where security scans and approves your boarding pass.

Anyway, he's learned his lesson (hopefully)!