Downtontrout.
Reading your post has made me feel so sad for you.
I was the 'younger sibling' of the situation in my family with my older brother much as your younger daughter is within yours .
It's horrible .
His situation was different to your daughters - but essentially the emotional abuse of my parents was the same.
Growing up , watching him twist his problems so that they became my parents obligations was horrible.
The older he became , the better he became at making them feel responsible the harder it was for me to witness.
I was also asked to walk on egg shells , keep quiet so as not to 'upset him' and god forbid if he found out if they treated me to something nice and he found out - he used to go mental.
Because it wouldn't be fair then would it , my parents time and their money spent on someone other than him - he was the 'special child' ( in his eyes ) & everything should of revolved around him and he should always be put first , even before my parents - hell no !
I'm afraid , you more you placate her , reason with her the more reasoning she will find to make you feel obligated , guilty etc and give her some money.
I'm afraid you have to be cruel to be kind - otherwise this is the way it will stay forever .
You may of noticed that 'my story' is written in past tense. Yes , it no longer happens . My brother is still entitled. But sadly in the last 10 years I have lost both my parents. His abuse of them happened until they both died and he could no longer ask them to bail him out.
This is why I plead with you to sort it now and not let it carry on,
For your younger daughter's sake. As much as for yours.
Everything in your older daughters life is down to her choices. Everybody needs to be responsible for their own choices - or at least be given a chance to be responsible for them. My parents as they always ultimately bailed out my brother denied him the chance to show himself as being responsible - why did he need to worry , when they did the worry for him?
Regarding the dog - it is nobody's 'right' to have a dog ; they are a luxury. Luxury costs - to take on a dog a responsible owner needs to be able to afford the luxury of one. Including food, vaccinations, worming, insurance for or vet bill costs etc.
Again it comes down to choice - if you did not make the choice , you are not responsible for the costs.
Although, I do see she is your daughter . She is no longer a child that you are obligated to provide for.
She is a married mother with her own child - one that she & her husband (and no one else ) is obligated to provide for.
I may sound very hard nosed , I'm actually not.
I would of loved to of seen my brother with a 'healthy' relationship with my parents . That's why I have responded to your post - I'm sure you would love a healthier relationship with your daughter too. But it's going to take some 'hard' work on both sides to get there.
I wish you luck & happier times.
Apologies if I have gone on.