She won’t have anyone to “backbite” to if you and your dad are not going to hang around when she starts up with that. Backbiting is no fun if there’s nobody listening to it. Don’t feed her habit, PCG.
Tell your mom about backbiting with Islamic reference. PRINT out references from websites and have her read it. Tell her that** “Look, Mom…if your frequent backbiting is TURNING OFF your own child and husband…can you imagine how others might be feeling. If it doesn’t bother you that you’re earning gunnah from Allah for backbiting…keep in mind that the listener also receives gunnah for listening to gossip. Why do you want me and dad to earn Allah’s punishment just because you can’t control yourself. I care about Allah’s judgment so i’m going to remove myself when you start being negative. It affects health.”**
You said that she’s a housewife who has been laid off. Well…when there’s nobody around to “manage” “nag” discipline" “complain to”…maybe she’ll see that you’re SERIOUSLY bothered by it. Actions speak louder than words…and as the saying goes…seeing is believing.