AIBU to refuse looking after my sister's children more?

Totally agree with other posters who said don't do it.
I'm wondering why your sister put herself forward for a job were weekend work was part of the deal ?
And saying that she won't be able to take the job unless you take her kids every weekend is putting the onus on you..which is unfair and bloody cheeky..

This is really cheeky. I assumed she was a single parent until I read further on that she had a partner. This isn’t your responsibility! They chose to have kids so they need to do what every other parents across the world has done and work out the logistics between them. If they can’t, she’ll have to look at different jobs. Do not give up so much of your time to do that!!

I wouldn't even do what you suggested to her. You have 3 children and a full time job and a husband with a full time job. how she and the father of her children manage their work schedule isn't your problem to solve. I would happily help out on a weekend day in a crisis but that is that.

Sounds like a lot to take on especially as you are so busy. Seems unreasonable to me.

I wouldn’t be doing a single weekend! Your offer is too generous as it is!!

This is too, too much. Say no to all of it, you’ve served your time, your sister needs to find a job that will work with her need for childcare . Is she paying you for this childcare, by the way?

Good God that’s a terrible ask of a busy woman, sister or not. Blooming cheek I think. I see the voting is 99/1 currently. That must be your sister, I can’t imagine anybody else thinking that is fair to you or your family.

God no, you deserve down time too. She should not of had more children if she didn't have some kind of safety net.

I cannot believe she has asked you this. What an entitled attitude. The cheek of
some people never ceases to amaze me.

This!

"So, to sum up, you want me to work seven days a week, every week, until your kids are old enough to be left home alone for full days"?

Might make her realise how daft she's being.

Yanbu. My husband and I both worked weekends. We just had to make sure one of us was off to look after our children while the other works. Because our childcare wasn’t open at weekends. Such is the juggle for many families where both parents work.
what you’ve offered is more than generous

Your sister sounds very entitled, you’ve done enough, and giving up your weekends is a huge ask.

I’d stick to your guns and let it be a definite and final no.

You can't have two shift workers in the house unless you get set shifts or work around each other, that's a problem for them to solve, not the Op. I wonder if they've even looked into it or if it's just easier to palm your DC off on the nearest female relative

No.
No is a great word & a complete sentence, If she keeps on, have a cigarette in the corner of your mouth & a glass of something over ice in hand whenever she approaches your home. Seriously NO is the correct answer.

Your not being unreasonable. Surely she would want to find a job that allows her to have at least some weekends off so she can actually spend time with her children once they start school. I've changed jobs to be able to spend more time with my children. I think most parents have to try and change their work hours or change jobs completely when they have children. It would be easier to find a childminder/nursery for her children if she works during the week as well. It's not fair on her putting it all on you.

As I have said upthread: the OP needs to be careful that, once she says no, her sister doesn't try to pressure the OP's own older children to do this childcare. She sounds pushy and brass necked enough to do this, and many young people can feel guilted and uncomfortable at saying no to a request from a family member despite being daunted by it. The odd couple of hours' babysit for pocket money - fine. Giving up precious weekend time when they should be studying, resting, or just having fun? Absolutely not.

The ever lasting list of symptoms are unfortunately a thing with peri menopause / menopause

Your sister is entitled and out of order. It’s something she needs to work out with her children’s rather, it’s their issue to sort and not yours. She’s had the luxury of being off for the last few years which is more than most people get and they now need to work out a plan that works. You’ve offered her more than l would be willing or able to do. She needs to work on being grateful as well

Either her or her partner or both of them could put in a flexible working request to ensure they aren't both rostered on the same days. Everyone has a right from day 1 of working and the employer can only refuse if the business can't accommodate it.

Christ, the cheeky arse of some people. She asked, you say no, then she tries the guilt trip on you even when what you have said you can do is waaaay more than I think anyone on here would put on the table. She chose to have younger children, she can sort out childcare for them and personally even offering one weekend each month is still too much, you will be committed and that will encroach on your family or a bit of you time. Fuck that, and on top of menopause lurking in the shadows, absolutely not. Do what works for you, you are bringing up your own children, leave her to do the same and don't feel no way about it.

Well you are very generous regardless. Most people would definitely not want their sibling's young kids to look after every weekend.

Has she accepted a job without checking with you first or is she just figuring it out?
You have been very generous. Stick.to your offer. She wants everyone to make changes to accommodate her except her and her partner.

She may not find a childminder too easily either.

If your sister (and her partner) work weekends presumably they have time off during the week. Has she offered to do school runs for you, or your housework, on the days she's not working? Why does she think you should be busy 7 days a week when presumably she has a couple of days every week when her older child is at school and she isn't at work? You are absolutely reasonable to tell her you can't do any more childcare than you have already (generously) offered.

I think you've been more than generous in offering what you have. Your sister sounds the unreasonable one.

I’m worried about your symptoms (I don’t want to derail the thread but…) have you spoken to you GP about this? I’m sure you have, (I’m beyond perimenopause now) but I recall that in peri I was told that the combination of heavy frequent periods and anaemia was a red flag.
Also, don’t do the childcare. She needs to find a different job. An absolute cheek to ask you!