How do I support hubby when his narcissist mum lives with us

Hello all i am in desperate need of help my mother in law is a narcissist and hubby has so many self esteem issues and thinks he's worthless due to her using him as her scapegoat I try and build hubby up with praise and with all the wonderful things he does for others and our family to which she destroys in one minute. To make matters worse she invited herself to live in our home and since then has pitted us against each other told his siblings lies about me runs me down to hubby's church and when confronted she lies even more I come from a very open and honest supportive family and struggle with all the back stabbing lies and deceit. Hubby is finally aware of that she is a narc but her grip over him is iron clad he's so de sensitised to it all he doesn't realise when she's manipulating him and I love my hubby so very much and want to support him in everyway possible but this women is making life hell we recently lost a child and she constantly went on about having to leave her dog due to moving here. I know you awesome people will have some advice and is greatly appreciated thank you so much.