It's often best to check what is going to be deleted with obj.delete() before actually running it, and the way to do it can be found, for example, here: https://stackoverflow.com/questions/12158714/how-to-show-related-items-using-deleteview-in-django

TL;DR:

from django.contrib.admin.utils import NestedObjects
collector = NestedObjects(using='default')
collector.collect([obj])
collector.nested()