Bipolar mum advice

For issues specific to caring for someone with mental ill health.
My mum lives in a council flat with her husband. They are having problems with the neighbours who are very spiteful even though mun has nothing to do with them. They had problems with the neighbours last year too. Mum's husband works most of the day and mum often sleeps until the afternoon. Mum's husband said that the situation is making mum depressed and she is scared to go out. He wishes that mum could move with me until He can sort out either a flat Swap or get a help to buy property
I care for my nan who has dementia and live with her in the family home. The problem is that although mum loves me in her own way i don't get on with her, i overbearing bearing. Her husband says that she would stay primarily in the 2nd living room and her bedroom. My Nan gets on better with mum in short periods of time. Mum has in the past agitated nan, been really rude and horrible. She and her sisters don't get on so she took it upon her self to moves some of their photos from the display. Mum has also kept going on about nan's will and on top of that talks a lot, mostly about other people. (I am a quiet person btw). I don't trust mum also because due to her bipolar she twists or tells white lies. Once last year mum was looking after nan whilst i was out and must have become aggravated (dementia) and rude, mum didn't back down do nan got worse and mum called the police on her. Sometimes mum's mood can be fine but then sometimes she gets high.

I really don't want mum to end up staying here. Her husband said that she is my mum and i should help her.
I don't know what to say or do!? :(
Do NOT let her move in.

Yes, she's your mum but she is also his wife and HIS responsibility, that's part of being married!

What help are you getting for nan?
Does she own, or rent the property?
Are you getting any time off at all?
Nan owns the house.
I have a day off once a week whilst nan is at a day centre and i leave nan at her friends house down the road for a few hours on evening a week so i can do an activity.
Can I ask how old is your Mum.
https://www.bipolaruk.org/
You may get some advice from the above.
You Mum's husband now has responsibility. Yo have enough to contend with.
It would seem you Mum needs some one to visit the home. Give her reassurance and possible encourages with support getting her outside the home.
Yasmine, that's really not enough time to yourself.
Ask Social Services to do a Needs Assessment for Nan and a Carers Assessment for yourself.