The Dark brotherhood was falling apart before our PC met up with the organization. Astrid was driving it down. Go read the letter that Maven wrote to Astrid in her room in Riften.

He did right by trying to kill the cow.

She was doing everything she could to keep it afloat, and was doing a better job than most considering hers was the only remaining Sanctuary.

She should have made way for the Listener, no question. But she was doing a good job making sure her Family stayed together.

keeping your family together or your servants obedient is hardly the same thing

When astrid took over the dark brotherhood vanished. No night mother, no listener, no dark brotherhood. Just a band of thugs getting by on reputation they didnt earn