Originally Posted by
CALfly5
.. If the ticket is purchased (with cash) for your friend as the traveler (either they can buy it or you can buy it for them - they must be the ticketed passenger), then you can use your miles to request an upgrade for them. That upgrade request takes on the priority granted by your status. Since the miles will come from your account, United’s system knows what your status is. Their status is irrelevant in this scenario.
This mostly incorrect
As a single traveler, the use of miles by a non-traveler to requested an upgrade will provide no priority benefit. It will be based on the travelling passenger status not the mile provider. exception is if the mile provider is a GS, if so the individual will be on the PN list but still at the traveler's personal status.
If the elite and the other individual are on the same PNR and the elite uses their miles to request the upgrade for both then the 2nd traveler with inherit the elites status priority.