The In Law You Never Hear About

So my brother is married to a girl named Jen.  Jen and Kerry got married two days after Marlow was born, but they have known each other since highschool.  She is three years older then me, and three years younger then my brother.  It was sort of romantic how they ended up together.  They dated in highschool in a different city, then Kerry(my brother) moved home.  Jen sent out hundreds of letters and made a ton of phone calls until she located him.  It took her two years.  Finally they got in touch and she came down for a visit.  And decided to move here.  She always said Kerry was the one who got away.  And he felt the same way.
When she moved down I was living with my brother and another room mate.  Neither I nor the room mate had any problems with her moving in.  But a few months after she moved in, the room mate moved out(don't know if it had to do with her or not) and then Jen started filling my brothers head with ideas about how the place we were in was gross, dilapitated.  Not fit for inhabitance.  It wasn't a palace, but it was fine.  More important, we could afford it.  But Kerry finally agreed to move.  They said I could come with if I wanted too.  Well, at that time(I was 17) I had no choice really.  I still couldn't get someone to rent to me on my own since I was underage.
They rented this brand new fourplex, it was almost 500 more a month PER PERSON for rent.  I was working my ass off to stay there.  And Jen was getting crazy anal.  She would do things like scrub the sink with a toothbrush after the dishes were washed, every time.  And mopping three times a day.  And she expected everyone else to do it.  She made out chore lists like we were children(we had another roomie in this place).  It got unbearable.  I remember once I was eating some soup and I set it on the counter so I could go to the washroom.  I came out and the bowl was gone.  I thought it must of gotten cleaned up.  But when I went downstairs it was on my bed, upside down, with a note that said 'clean your shit up.'
Needless to say, I moved home.  I couldn't take her anymore.  So I went home with my tail between my legs and paid my mom rent for about eight months.  I did some college courses while I lived there. 
After the eight months Jen, Kerry and I had a talk and they asked me to move back in with them.  They were buying a trailer and a renter would help, I would have a set rate and that would include food and utilities.  Plus, they were expecting and they said if I babysat when the baby was born they would take it off rent.  I reluctantly agreed.  I loved my mom, but living at home again was no picnic.
This time Jen was the OPPOSITE side of the spectrum.  She didn't clean anything.  She left dirty dishes all over the house, she never swept, vaccuumed, dusted.  She lost the baby shortly after we moved and Kerry started catering to her hand and foot.  It made her go even worse in the filth.  I had two cats, and she had two cats, but she informed me that she only wanted three cats in the house, so I had to get rid of one of mine.  The neighbour we had at the trailer park agreed to take my one cat, since he loved him.
I met Joey there, and I moved out with him.  Jen pitched a fit when I moved.  I gave them three months notice, and I told them I wasn't living with them forever.  About a year after I left they lost the trailer to the bank, Jen declared bankruptcy and they started all over again. 
Jen got pregnant again(before they lost the trailer), and Shay was born on St.Patricks day.  They doted on her.  But when she was one, they got pregnant again and Jen got depressed.  She didn't want another child(she had a kid older then Shay but it was given up for an open adoption).
Jen isn't a BAD mom, but she isn't a GOOD mom either.  She is short tempered, she expects her kids to be robots, they are laid down for three to four hours every afternoon to 'rest' wether they sleep or not.  They are expected to lay in their beds and be still.  They are 2 and 3 now.  She expects them to eat no sugar whatsoever.  She gets mad if people get them birthday presents of Christmas presents.  She expects her kids to watch other kids open gifts on holidays and be thankful for what they already have.  She does not take them to the park, or out anywhere.  My brother is actually the more active parent.  He cooks all their meals, he does all the cleaning, he bathes them, he potty trains them, he puts the to bed and gets up with them.
Now, Jen has her own cleaning company, and it's taken off enough she doesn't work for it anymore.  She has employees.  So she got a job in her spare time(go figure) that has her travelling on weekends and working all hours.  My brother also works a full time job, he manages the computer department at a local chain retail store.  But they are always broke as they live outside their income.
Now, the other day my mother was supossed to watch Shay and Tova, and I was in a pinch for a sitter so she offered to watch Marlow too.  She said she would show up at my place early, then Jen could drop the kids off at my place.  She was going to give me a lift to work then take the SUV and the kids out somewhere fun.
Jen shows up 3 hours later then when she said, and she is all rushed and cranky.  The kids are at my door and mom hollers out 'I need the carseats hun, I'm taking the torrent' and Jen snaps!!  She yells at the kids to get back in the van, she's running late and doesn't have time for this shit.  She shoves them in the van, buckles them, and peels out.  Now my mom feels bad.  And then Jen texts her and says 'we don't need you to babysit Tuesday's anymore......thanks anyways'.
Tuesday is the only day my mom gets to see those kids.  They see Jen's mom about three times a week, but Jen doesn't like being around my family so she doesn't want her kids around either.  It doesn't seem to matter to her that they are my brothers kids too.  So now my mom doesn't get to see them at all.
And my brother!  My 6 foot 6 inch tall brother is so kow toed by his 5 foot 2 wife.  Seriously, he is scared of her I think!  When we go over there she is always 'resting' (locked in their bedroom) and he is always chasing the kids.  He says, oh, well she's tired.  What about him?? He works too, more then she does!
And Jen will let her family do something with the girls and then if someone in my family tries the same thing, she snap shows.
I'm getting really fed up with her.  Once upon a time we got along really well.  But she is getting worse and worse.  No one in my family want's to be around her anymore either.  And that's not fair to my brother.  He needs his family as much as she needs hers, but hers seems to be the only one that matters to them.  But I think it's because he is scared to speak up.  Even his best friend is starting to get fed up with her.