How to split payments fairly?

[NCforthisdilemma]

Opinions please as not sure if I'm being fair.

DDad milestone birthday coming up, 3 siblings, DB plus DSis and I. In the past we have done meals out, shows and holidays. All siblings agreed to treat DDad to a holiday this time. DSis has now decided she would rather not come, no particular reason, just would rather stay home, and has asked to just pay an equal share of DDads costs. I feel cost of whole trip should be shared between all 3, because if none of us went DDad would get no holiday. So in effect, I'm asking DSis to subsidise our holiday costs for a holiday she is not going on (but that other siblings wouldn't choose to do if it wasn't for DDads birthday). Am I being unfair to expect DSis to split whole cost?

(No one is short of money, all earning)
UK based holiday, not huge costs, max around £800 total (edited to include rough cost)

I'm with your sister.

sweet jesus i’m with your sister in this one presuming the holiday hasn’t already been booked

adjust the holiday cost to reflect your sister isn’t going as presumably not booked yet

and leave her alone

and think of your poor dad if you create drama over this

come again

a holiday for £80?

ah just seen your edit

YABU. Your sister should only pay towards your fathers.

If you’re not short of money why are you even moaning?

Is it a holiday where 3 bedrooms will be cheaper than 4?

Why should your sister pay towards you and your brother ? Are you definite that she doesn’t have money issues?

It’s a shame that she won’t be going as that would be part of the treat for your dad.

I'm thinking reverse.

I'm reading comments and if most agree with DSis I will drop it, haven't brought it up yet, just niggling me. DSis definitely no money worries, and her not coming will not reduce cost. DDad will be disappointed that she isn't coming.

Haha its not reverse, just trying to present it in an unbiased way.

Not enough info on costs to be shared, but I suspect something in the middle of the two would be fair.Is it just the accommodation, which is a 4 bed?

wtf

you will “agree” if the majority of anonymous mumsnetters tell you something in unreasonable rather than just…. engaging brain and thinking for yourself that this is utterly unreasonable of you

Whats your DB’s view on it?

Its just the accommodation, travel costs paid separately (each paying own)

£800 total cost for 4?

Bloomin heck op i’d be a bit embarrassed if i were you!

@crayfishyum that's why I'm asking, I can't decide if I'm being unfair in expecting this, you clearly agree with DSis (which is fine). To re-iterate, DB and I are going on holiday with DDad to accompany DDad, and would not choose this holiday otherwise.

What’s your DB’s view on it?

does your sister have children?

God imagine how he would feel reading this.

exactly

and it looks like if we had agreed with the Op, she would have gone ahead and created drama

I agree with DSis, you spilt your dad costs between you and each pay their own.

Those going on holiday should pay the holiday cost.

Your DSis is being kind offering to pay a third for your DF given she is not going.

I think you're being really unfair. There must be some backstory?

DSis/DB have no children, I have one (saying home with DH).

Even though we all agreed to take DDad on holiday?

She's paying the third for your DDad? So you are all taking him on holiday.