how to please DIL

Find the humour in her blatant cheekiness. I would say “that is parenting I’m afraid” when they have to take time off, and laugh and the nonsense of it.
she is irrational and bit mad, so you can’t reason with her or SS by the sound of it.

Next time she says "jump" you say "how high". They don't appreciate you and want to cause you trouble. Did you get on with your SS?

I don’t think that a £50 gift is a token gift at all? So maybe OP should just stop putting the money away??

Why is she annoyed with you and not her own parents? They were away too. As upthread, they've weaponised the baby. You need to nip this behaviour in the bud as it will only get worse when they need childcare in the school holidays.

Me too.

how to please DIL?

The simple answer is you can't.
You just have to do what you think is right and let her react however she's going to react.

I don't think OP is doing any childcare.. there's nothing in her post about them actually doing any?

She did get a gift, and spent £50 on it, so hardly a 'token' amount in my book.

Why are you looking after their kid, did you want to or did they persuade you? The kid isn't even your grandkid if they're your stepsons kid. Why can't your husband, stepsons mother or her parents help out or better yet they can get paid childcare.

she is unhappy that we went away on holiday in March

DIL is now moaning that we didn't get the baby much???

apparently its our fault they are not available in April for a visit as DIL is away every, yes, every weekend in april and again bemoaning that they do not have childcare and that SS is now having to take leave from his job?

How do you know DIL is unhappy with you, is she telling you or is SS the one telling you they are unhappy & what has one got to do with the other (not being able to visit weekends & not having childcare?)

(the holiday in march was booked last year, well before the baby was born) and we assumed at this point the baby would be going to nursery, but apparently, even though he has now free hours? she doesn't want him in nursery?

It was wrong of you to assume anything to be honest, it's not relevant, neither is it your place to question their decision to put child in nursery, absolutely nothing to do with you. But, what has your assumption got to do with the fact that they are annoyed about lack of childcare, did you not tell them about the holiday because you assumed they would have childcare covered.

It sounds like her parents do regular childcare, but they are away that week and they assumed you would be available because they didn't know about your holiday?.. so they've had to sort themselves out last minute instead?

It actually sounds to me like you don't do ANY regular childcare for them, but the times they have asked you to do it you've always got a reason why you can't do it? It can be frustrating if you've offered to do it but the don't ever step up when they need help.. had you offered to help with childcare?

She sounds outrageously entitled and grabby. I think you need to start doing less for her and your DS, not more. DIL doesn't sound at all grateful for your generosity.

Your DIL is a cheeky fucker isn't she?

I would take a complete step back from any childcare and any gifts and I'd be telling her / them why.

My MIL and FIL have provided us with childcare when the DC were smaller and my gratitude to them is endless. We'd cover as much of the school holidays as we could so they just had to do after school pickups. We'd buy a food shop for them every week, and we'd tell them to always, always, always put their own lives first and never make plans based on looking after the kids.

I cannot believe people are actually this entitled!

Honestly, there is no pleasing them so I would stop trying. Also sounds like something your husband should be sorting with his son.

Your DIL clearly doesn't understand the concept that this is her child and her responsibility! She sounds like a spoilt brat, and very grabby.

Drop the rope and pay her no further attention for now. It doesn't stop you from sending birthday cards with some money in for your grandchild and/or paying directly into his bank account.

Leave the communication to your DH and your SS for now. Are they aware of how rude and entitled DIL is being? Make sure they are.

She sounds like one of those people who think that the world, and particularly the grandparents, owes her a living because she has given birth. It doesn't, and you don't.

I'm sure you want to know your grandchild, and you sound very kind, but you are entitled to a life too, and your holidays, which I hope you enjoy. 😃

Yes and the child is 14 months old, they won’t have a clue how much a gift cost, you could buy something for £3 and a 14 month old child would be happy. I bought my DNphws colouring books and crayons for their 2nd birthdays and wooden jigsaw each from home bargains, they were over the moon with them. It’s not the children who understand cost it’s the parents. By the time they understand the value of money they will understand they have X amount in a bank account from their GPs and be ecstatic, well as long as they don’t take after their parents.

DIL sounds very selfish and grabby, I wouldn’t even bother going forward and just let your DH deal with them.

Really? At 4 neither of my kids would have really noticed (assuming no presents were being swapped in front of them without them getting one!) and it would have been easy to prepare them that they wouldn't be getting everything from us / Santa and no extras. Particularly as that meant getting everything earlier!

Even now my teenagers wouldn't really care and don't seem to keep track of how much is spent on them by family.

Your dil is biting the hand that feeds her. We have dgs for 2 days and 1 night per week (he’s just turned 2). When we go on holiday either my dd or dsil take annual leave. No way would they create over us going on holidays.
And put your dgc savings into an account they can’t see.

Your DIL is rude and entitled and your SS is sitting idyll by watch it. They aren't entitled to childcare or gifts. I don't actually remember any gifts I've ever received from my grandparents but I do remember the day trips.

Our inlaws always let us know when they would be away in advance (they used to have DDs one day a week). We made alternative arrangements and it was fine- they are allowed to go on holiday! We were grateful for their support.

But she spent £50 on the birthday gifts and the child was only 1. I think that’s MORE than enough?!
I have 2 kids and we’re overrun with toys-I’m always delighted when someone chooses to gift an experience/ day out/ cash in an account. So much more practical. Either way, I’d never complain so I think your DIL is being a CF.

we assumed at this point the baby would be going to nursery, but apparently, even though he has now free hours? she doesn't want him in nursery?

Why would you assume that? Research has proven it is more beneficial for a child under the age of 3 to stay at home with a primary caregiver.

I also didn’t want my two in nursery before 3.

I don't think there is any pleasing you DIL/SS in the above.

In terms of the childcare, even if it is weekly specific days childcare, any rational person would understand there will be points of the year where you want to take holiday and won't be available (sickness) for childcare. Your DIL/SS should have factored that in when they asked you to provide childcare or when they accepted your offer to provide childcare. This is the whole reason I would never ask or accept childcare help weekly from family. I wouldn't work with us having to take time off if that person was away/sick.
If its adhoc childcare, they have to no right to expect family to be free so they can attend social events. If they want to go and you are away, they need to find a friend or a babysitting service not moan you aren't around.
The factor they don't want to send their DS to nursery should not mean they put that on you. They need to sort out the childcare around that, and understand the logistics of accepting family help.

In terms of the money over present, I think your DIL/SS are being very short sighted about it. My parents started doing this a year or so ago (for DS7). I'm so grateful they have. I'd much prefer my DS to have a little nest egg for uni or whatever he decided later than lots of presents now. You get to a point where you just have too many presents for every birthday / christmas / event etc and they don't appreciate what they have. They do what you do with token present (around the £50 mark) but its dramically reduced from what they use to give him.

If you want to carry on the childcare, then I would be very clear about when you are going on holiday and that they need to sort alternative arrangements out. Give as much notice as possible when you book holidays.

THIS !

What childcare do you provide - is it a whole day/overnight? Every day? Some days? Every weekend?

Did DDIL actually complain that your birthday present or did she say something like 'he didn't get much for his birthday'?

What is your DDIL's social activity?

I agree with pps that this is very cheeky behaviour but assuming you want a relationship with the baby I would advise staying calm, ignoring whinges about presents, clearly state what you can/can't do in terms of childcare, and maybe accept for now that you may not be as close to DIL as you'd like.
Are there any mitigating factors in their behaviour eg are they very young, was the baby unplanned, does baby sleep through the night? (You don't need to tell us, just some things to consider). It doesn't make their behaviour ok but might explain it.
lots of parents not only have no or minimal practical help but also have to help their older or unwell parents and juggle that with looking after their children. So your SS and dil are very lucky to have two sets of grandparents able to help.