How do I get my Brothers Scanner ADS 1500W to work with the update?

Did you try scanning directly with Preview or Image Capture?

My Brother scanners work just fine in Catalina, even though the Brother software does not.

I just open Preview and choose File->Import from Brother DCP-197 (or similar, not at my mac right now)

I am assuming that prior to the upgrade your scanner did work. Some scanners seem to no longer work with the last OS upgrade. As I see it you have the following options; (1) file a trouble report with Brother and keep checking for an upgraded software that works, (2) Use Apple's Image Capture app. It will scan, but without additional features, (3) download the VuScan app. It works with most scanners very well and provides a lot of additional features. Download the trial version to ensure it works well. Then if it does, there is a reasonable purchase price for the software. Details are on the web site. Good luck.