softer_delete_all_dependents.rb

module SofterDeleteAllDependents
  extend ActiveSupport::Concern

  included do
    before_destroy :softer_delete_associations, prepend: true
  end

  private

  def softer_delete_associations
    associations = self.class.reflect_on_all_associations(:has_many).select { |v| v.options[:dependent] == :delete_all }

    associations.each do |association|
      if association.klass.included_modules & [SofterDelete::UsingIsDeleted, SofterDelete::UsingIsNotDeleted]
        model = association.klass.new
        model.send(:prepare_for_soft_delete) do
          send(association.name).update_all(model.send(:soft_delete_attributes))
        end
      end
    end
  end
end