Maybeeee.... she didn't have all of her "faculties" back when she said you were a bad mother. Maybeeee... she's always been a little Cra-Cra....LOL
There is not much worse than to have your mothering skills attacked. I always think the opinions of people I don't know have of me is totally dismissable. Not that anyone ever had a bad thought about me or anything. 🤣
I'm glad you happened along when you did and didn't choose to reward her previous ugly remark with your just walking on by and leaving her there to her own devices.
I have wondered about the functionality of her faculties for a long time too. Maybe she has always been off. Or, maybe being exceptionally grouchy qualifies as crazy, simple because it is different from everyone else?
I try to let other people's opinions roll off too. Some are harder than others though. It is a skill that requires a lot of practice.