You don't need to be on the same PNR to get a companion upgrade. In fact, having separate PNRs will prevent boss from losing upgrade priority due to requesting an upgrade for you. Boss can also call and have you put into a C+ seat for free, but not for more than one person.

In practice, if you go to the airport together, you're likely to be permitted to check in with boss in the elite line, get a free bag, and use elite security together if boss does (rather than PreCheck). You can probably also board together in the boss's boarding zone.