I am also glad to hear it turned out okay.
I hope I did not come off as alarmist last night, but with my SAR hat on, it is better to be called early and turned around than to get called late and wonder if you could have changed the outcome.
Knowing when to call for help is tough - but that is one reason SAR is FREE. If your gut feeling is that something is wrong, I would at least want to start talking to someone from the local SAR team. The Whitney trail is notorious for making people miss their out time, but as the story was told, no one had seen him since 1pm. Also thrown in was some AMS. Calling in to give the dispatcher a heads up that someone was missing did not cause any trouble, and if he hadn't walked out by the morning, resources would have been getting ready.
For anyone else who finds themselves in a similar situation, there is some information gathering you can help with before the local SAR assets show up. If you know a place that the missing person walked or sat to eat lunch that left footprints, draw a big circle and don't let anyone else trample them. Start making a list of what the person was wearing and what they were carrying. If you are at the trailhead, politely ask anyone else finishing their hike if they saw the missing person. If so, where and when and how did they look. Hopefully, your friend will walk out a little late and at least it was something to do while you were waiting.