Divorced mum dad trapped under same roof

Hey guys, hope we're all keeping well and safe ❤

I have an interesting question for you and would appreciate any feedback or advice to pass on.

Okay my mum and dad have been seperated (divorced now?) Living under the same roof for 3-4 years. Unhappy with one another for 15?
But they get on well, both pay 50/50 for bills, mum would cut his hair for him, they would chat but nothing too much, don't hang out on the lounge together or make each other meals anymore. They do do trades, ie lasagna for servicing my car etc.

They've been working on the house to get ready to sell, its been slow going. They have alot of atuff in storage to work through etc. Their house though is teeny tiny, a 3x1, the size of a unit, really small.

Dad went last year and did seasonal work, so was away for ages and only came back in November. Now i know hes been dating, mum didn't, i understand dad is lonely and really wants to move on and meet someone. Which he did doing his seasonal work, good for him!
But as mum was going to house sit at my sisters house for a month he drops it on mum, I've met someone and she will be coming to and from the house while your away. Shes couch surfing and has nowhere to go.
Mum rocked up the day she was meant to be leaving to go to my sisters and the new lady was there, mum noticed she had brought a suitcase with her. Mum said to her not to touch her stuff or go into her room, the other woman just belly laughed at mum and said 'i'm not like that!' to which mum replied 'i dont know you, your a stranger'

Fast forward a month of mum crying and having anxiety wondering if this woman would be moved in while she was away, if she would go into her room and touch her belongings.
Turns out she was helping dad go through the storage container (something mum and dad agreed on they would do together, being alot of memoires and things like that stored in there).

So mums back at home, new lady has NOT moved in but still having anxiety having to see her and deal with her.
Dad introduces new lady to us kids, she seens nice, I like her, she makes my dad happy.

Fast forward to covid-19, mum is now working from home, cant leave the house, can't stay at friends, go get a drink etc.
Dad hasn't worked since Nov, is no longer able to pay for half the bills, the buggar even had the nerve to tell mum she should move out, but fingers crossed there's still money in the sale of the house so mum doesnt want to move.

Now mum is crying every day seeing them together, holding hands, laughing.
She loves dad but doesnt want to be with him but also doesnt want this in her face day in day out.
Mum told dad she doesnt want new lady coming around anymore, 10 mins later new lady rocks up, so mum says same thing to her, with tears in her eyes, she told her how uncomfortable it is being around them and wishes they would go somewhere else and not come here anymore. Again new lady belly laughed at mum and pretty much told her to get used to it, that shes couch surfing and they have no where else to go.

Nowwww the big one, whats the next step, this woman starts sleeping over, dads room backs onto mums 😪 mum brought this up with them and they again just laughed it off.
Mums crying daily again, what a living hell.

Cue me, ready to have bloody strong words with dad and new bird but mum wont have a bar of it, doesnt want to seem bitching about him or play nasty games.
Mum hasnt told anyone else, i have 3 siblings.

Told my hubby, he thinks dad is a total dick, absolute dick move and mum should kick him out cause shes paying all the bills but i know thats not fair on dad either, theres been times he supported mum too.

This is the quick winded version, I wish my parents had seperated 15 years ago, instead they both lived unhappily for us kids 💔

Thanks for reading ❤ now halllpppppp what do we doooo???? Thank you xx