If you want an example of the ultimate in crew resource management, try this summary of a short report from the Irish Air Accident Investigation Unit.
The Air Canada Boeing 767 skipper turns up on time, but his first officer's positioning flight delivers him late and acting nervously. In the interests of setting up a harmonious flight the captain tells the first officer to meet him at the aeroplane, and not to worry because everything is done.
The flight leaves Toronto on schedule for Heathrow, where the weather is forecast to be Category IIIB autoland conditions.
Cruising at FL360, the first officer's demeanour goes gradually downhill, despite organised rest periods that the commander sets up to help him recover, until the captain is so concerned he calls the cabin crew to help the copilot out of his seat.
The crew finds medical expertise on board to attend to the copilot. Meanwhile the captain asks them to check the manifest for off-duty or positioning pilots, but there are none. One of the stewardesses, however, has a CPL with an non-current IR, so the skipper co-opts her to help manage flight deck tasks from the right hand seat. His comments indicate she was a real asset.
Because he doesn't fancy facing Heathrow at Cat III with less than a full crew, the skipper diverts to Shannon where the weather is good, and sets up medical help for the first officer on arrival.
The landing is fine, and the copilot is met by medical specialists and taken to hospital.
Recognising "subtle incapacitation" is important, but sometimes it's recognised too late and has caused accidents and serious incidents. This was a model piece of CRM in all respects.