I believe you will be counted as a pair (as if you were on the same PNR), so it will be all or none. You would just have to call reservations to link the PNR's so your companion gets to ride your upgrade coattail.
https://www.aa.com/i18n/aadvantage-p...e-upgrades.jsp
"*Your travel companion can be booked in the same reservation or in a different reservation when traveling on American Airlines marketed and operated flights. If your companion is booked in a different reservation, call American Airlines reservations to link the two reservations."