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

I’ve heard men saying they’re ‘babysitting’ because their partner is out doing xyz.
When does a woman EVER describe caring for her own children as ‘babysitting’?
However, posting all these principles and beliefs are not much help to the OP.
I think the middle ground is probably best.

Say no but be available for genuine emergencies. We can't keep enabling men to be this lazy/useless.

There's a Man who has it all post in this thread. Sarah asked her sister's husband to come and help her with the kids when her own husband has gone away because she couldn't cope alone without the house ending up a tip.

Wouldn't happen of course.

She needs to go and leave him to it. If the house is 'a horrific tip' when she returns, she should walk right out again and not come back until he's sorted it.

I once knew an incredible woman through work. She was the director of a huge company, very young and disciplined. I always assumed put her career before kids and was the best example of what you can achieve if you decide to stay childless. However at one event, I was gobsmacked to realise she had 4 kids, all young and school aged. Her husband manages all of them perfectly fine by himself!

Reminds me of an occasion many years ago when I told my neighbour I was going away for a few days without my husband, “Ooh don’t worry love I’ll make sure he’s eating, I’ll take him a hot dinner round every night”!! Where was my hot dinner when he went away?! He was a perfectly capable cook but she was old school 😂

And assume BiL will be telling all and sundry that he is having to babysit the kids while his wife is away enjoying herself.

Exactly. His penis gets in the way of childcare. We should pity him.

It also prevents him doing housework.

18???? They are around for a lifetime.

Eh? Why would any woman have to? Does his dick get in the way of him asking for help? He’s the one who can’t adult.

Why have children and then bugger off on a cycling holiday or holiday with friends? Do they not realise the children will leave at 18 and they only have this wonderful very limited time to spend with them? Baffling.

I’d say yes so that she feels ok about going away, then once she is safely away there would be an urgent matter that I’d have to attend to and I’d tell BIL that I’d be back later. Then leave him to it and go back in time to make sure he’d cleared up before she got back.

DSis wants to go away with friends for a few days and has asked me to come and stay/help because BIL says he’ll find it too much on his own

There are two options here. 1/ BIL is utterly incompetent; and 2/ BIL is competent but just wants to skive off or laze around and have someone else do it.

Either option, I would go. I would do nothing but ‘direct’ if and as needed. So essentially, my time would be spent on the lounge, with a book, giving BIL pointers/helpful advice/instruction whenever he asked for help. That would be my help. It would send a strong message. If he asks ‘what’s the point of you being here’, just respond ‘you said you can’t do it, I’m here to tell you how to do it, so that you can do it, it won’t help you with your problem if I do it for you’.

If he dares to indicate he is going out to the pub/football/gym, say ‘no, that won’t work, I mean when you go away SIL doesn’t go out because that just doesn’t work, how do you think it works in this situation, I’m here to help point stuff like this out as you have said you need that assistance’.

I would have it sorted for SIL return. One man, either now competent, or understanding he can’t be a lazy shirker.

@mindutopia Your DH …doesn’t call up the nearest woman and offload the parenting to her.

OPs DH hasn’t even done that, he’s even offloaded that to his bloody wife 🤣

Hopefully the grandparents in all this have already said not a chance in hell and he can parent his own kids and clean his own house.

Hell no, they should both be embarrassed. Unless they children have additional needs or disabilities. He isn't going to get any better at coping alone if you're babysitting him. He can get organised before she goes, get a food shop done and freeze some dinners, practise looking after his own bloody children whilst she's there. They're both being pathetic.

Your sister should be embarrassed to be married to such an incompetent wet blanket of a man and he should embarrassed of himself for having to ask for a woman’s help to parent his own children.

Makes you despair what men are capable of/not capable of/ but pretending to be this kind of grand human

I might agree to take the kids to the park or cinema for a couple of hours on the last day so that he can tidy/clean. I definitely would not be offering to clean someone else's house!

Not your circus not your monkeys. Any woman who decides to have 4 kids obviously knows that it will not be easy for her to take solo trips away while they're small. Where are the grandparents in all this?

If you agree to this once, they will be taking advantage of your for many years to come.

He could ask for help?

Not your circus not your monkeys.

As if a father can't parent his own kids and live like a sensible person in his own home doing his own domestic chores.

OP YANBU. It's bloody cheeky.

You mention that you do help out and spend time with the kids suggesting you live close by? If so and you want to help then why do you need to stay over?

Couldn't you offer to maybe take 2 of the children out a couple of times and do something fun rather than being at the house? I would worry that your BiL would be expecting you to do all the drudge stuff whilst he puts his feet up and watches tv.

I'm also assuming you don't have children to look after if your sister has asked you to do this.

Does he not have a brother or a dad who can help if he is incapable of adulting?

I understand about finding a middle ground to help your sis but coming home to a tip isn’t a big deal. I certainly wouldn’t help with housework. And PLEASE don’t babysit them while her DH goes to the pub or whatever.
Just don’t do much.