not to help BIL with the kids while DSis goes away for a few days?

Does he have different work commitments to her?

Hell NO!!! He doesn’t want “help” he wants you to do the lot!!! He is their father and he can parent his own children!!

Double standards! So he goes away, she has to cope. But she goes away, he needs help. Quite pathetic really.

But your BIL could ask for help

I’d help.
Ways in which I would help:
say ‘I’ll be over first thing’ and not arrive until 10.45
Go to the toilet for 45 minutes
put some sport on the TV and say ‘it’s nearly over though’ for 3 hours
play a wild chasing game with the children until they’re all in tears
say “oh I’ll change the baby” followed by “where are the nappies” and “and the wipes?” and “where do I do it?” and “how do I do it?” Then put the nappy on backwards and find the outfit a size to big right at the back of the drawer and say “well it was in the drawer”
Ask BIL for a cup of tea or what’s for lunch or start long conversations about mortgage rates every 10 minutes, preferably when the children are also trying to talk to him.

In reality I’d say “I can pop round for 2 hours on Sunday and take them to the park while he gets the entire house cleaned and dinner on the table. You do it by yourself, so can he”

Gosh what a pathetic species he sounds. We loved it when our mum went away. Dad couldn't cook so we went out for all meals, went to the cinema, days out etc. It was lots of fun and we all helped keep the house tidy. He managed to get us all on the 7.30am school bus as well as picking us up at 5pm by leaving work early.
Maybe she needs to train her kids as well as her "D"H.

Hard no OP!

No you aren't being unreasonable. Don't do it.
If he can't cope with 4 kids he shouldn't have had 4 kids.
I agree with it giving him insight into what he regularly expects her to do.

I really hope your sister is being overly anxious and he doesn't even know you gave been asked or want the help, because that would be pathetic.

Also, sod men not asking other men to help each other.

This is not your responsibility, whatsoever

And the emotional manipulation is astounding

This

My BIL works away and goes to festivals fairly often. Dsis parents the children because she is their parent. When she has the odd weekend away he takes them to his mums, every time. Yes they are young but if one parent can do it then clearly it’s not impossible. If it was the first ever time one of them went away then maybe I would offer help, but as the mum usually gets on with it I would expect him to learn to get on with it too

Honestly, never have so many children with someone that if you died, they wouldn’t be able to cope alone.

That's appalling.

Move in while she's away to ''help with childcare''
Absolutely not!
Would you not feel resentful when her husband comes and goes, doing his own thing, while you're cooking/cleaning/entertaining his four children???
By all means help out by taking the children out, bringing over the odd meal or visiting, but moving in is ridiculous,
Does he really need a live in housekeeper/cleaner/nanny?

OP, presumably you are asking this question because you are questioning your sister's request for you to assist your BIL while she is away. There is scant detail about the circumstances (any special needs, school hours clashing, father working very long hours, ages of children and so on).

You have not said whether BIL himself actually wants and asked for your support. Perhaps he doesn't and didn't.

One poster suggested BIL might ask his brother or father. To which you replied that 'women don't often ask other men'. Why do you assume it's the job of women to ask other women for support for fathers with their own children? Perhaps suggest to your sister that BIL could ask one of his male family members for help if it's needed???

The whole situation is an example of women enabling men's learned helplessness. Of course this father can manage, just as most men can, unless there are extraordinary circumstances. Please just decline and tell your sister to enjoy her break and let her husband get on with it. If the house is a bit untidy, so what? The father will likely have a great bonding experience with his children.

You're absolutely right O.P. my friends partner does this, when she has the VERY rare day/weekend away he gets the three kids and drives to HER parents and the grandmother basically just ends up taking over. He goes over for a VISIT and stays all day!

No I wouldn’t. I thought I’d been clear that I meant offer to come and do a bit of childcare as a bit of breather for him to do an activity. Any parent should be able to look after their children and the home for a short period of time. Me and DH are used to having each other around so we naturally have our own roles in the home but both of us can manage fine if the other one isn’t there.

It is he who should be asking.

Say to her you will so she can go and relax and then get a terrible case of food poisoning last
minute so he will have to cope on his own 😅

He sounds like he doesnt know how
It's scaffolding to enable succes stacking 🤷🏻‍♀️

2 of my fave methods that I use when teaching my toddlers new skills 🙃

He needs to grow up and parent his children

Why do women continue to have children with these feckless men? He’d be left to cope if it was my BIL and I think your sister is cheeky asking you tbh, he fucks off on cycling holidays leaving her to cope but the poor incapable man child can’t cope? Fuck that. It would be a hard no from me and I’d be telling her not to ask again if she’s going to continue to enable his laziness.

This really is annoying , absolutely double standards here .
My husband has never had our 3 children by himself and of course I did it all the time .
He would be working or away and I’m expected to manage plus do all the domestic stuff too

yeah see I think he would guilt her back if you did that.

Oh hell no. Absolutely not, the fact that he/they even thought this is giving me the rage on your/her behalf.

Sneaky! But a good idea 😁