Not sure whether I should ask this question in AA or BA forum

Between BA and AA they has misplaced both bags of my child(DC) travelling alone.

DC is flying DEL-LHR-CLT-DSM and checked in 2 bags

DEL LHR is BA, LHR CLT DSM is AA codeshare

Both bags didn’t arrive at CLT

As per AA tracking Bag 1 is still at LHR, and bag 2 has reached DFW and has been loaded on DSM flight. Air tag also confirms the same.

What are the options does DC have? DC would be landing at DSM tonight.

With whom DC should file complaint? BA or AA
How to get luggage to DC? DC is 100 miles away from DSM
Bag 1 is reaching DSM midnight 3hrs after DC’s flight. How will DC get the luggage?
Any intermediate support that DC can get?

What else?