https://www.mercari.com/us/item/m93667757229/
If you start googling to try and get a ball park note there are some variants where the ATMOS is not below the 12.
Don't know if it matters or not.
They seem to be all over the place, between $700-$4,500 on the high end.
$2k seems to be the middle ground and as mentioned, condition, paperwork, original box all add to the value.
Good luck with moving mom.