My wife and I are Presidents Club members, and a few years ago the JL Sakura Lounge would not let us bring in one child each as a "guest."

That said, if he is arriving in NRT with a 3-hour layover, perhaps you can bring him to the NW WorldClub for a half-hour or so.

There is an airside bus between Terminal 1 and Terminal 2. However, if he is "too late," he may have a problem getting on the intra-Terminal 2 "train" if CO will not issue the boarding pass. This almost happened to me one time with DL. And of course, the boarding passes were issued in T2.

If there is any way you can get his NRT-GUM boarding pass issued when you check yourself in, that would be great -- I know, highly unlikely.

I know this doesn't help you now, but I understand that in a few years, CO and DL may be moving over to be next to their SkyTeam partners in T1.