Quince trees will often produce suckers from their base. They tend to be grafted fruit trees and the suckers sprout from the root system and take precious energy away from the rest of the tree.

My husband felt he might have overwatered it. I read what you wrote about the loss of black-looking branches just falling off trees and keeping suckers trimmed to ground level (too late).

This is a bacterial disease that affects quince, Asian and European pears, and apples. The first sign of fireblight appears in branch tips, which dry out and turn black as if they had been burned ...