Front speakers not working after battery install

[mrunsky]

My 85 year old friend has a 2019 Outback. In August, he had the battery replaced at the dealer. Since then, no audio from the phone is playing through the speakers. Prior to the new battery install, phone worked fine. All other audio works. Took it back to the dealer and they determined the front speakers don't play anything, no audio, Only back speakers work. I have a 2018 Outback, phone works fine. I tested it and found that the phone audio only plays through my front speakers. Dealer got a code of B2253 when trying to figure it out. I googled that and looked through the Subaru Service Bulletin of 2/12/21 and found that code. As far as I'm concerned, the code does not apply to the 2019 Outback. He does not have a Rockford Fosgate audio accessory installed, which that code mentions. Dealer recommended to have the head unit replaced for $900. He's 85 and cannot afford that. Does anyone have any ideas as to why the front speakers would not work after a new battery was installed? Is there something I can try to resolve this?