I don’t think either me or John’s sister’s husband would get away so lightly with calling our mother in law by a jokey nickname
Especially seeing as she referred to Mike (who is a really lovely man) as ‘your sister’s husband’ while talking to John recently
36 years as his mother in law and she’s never accepted him. I remember doing T’s hair on her wedding day and she was annoyed that her mother had just told her, an hour before leaving for the church, that if it didn’t work out she could always come back home.