To feel disappointed at DS Grandmothers refusal to help

[Ticklemonster2]

We are yet again potentially stuck for emergency child are tomorrow due to my ds possibly having conjunctivitis.
My MIL is the only living grandparent and is constantly telling us she wants to help with our son. However, there have been a few times now when we have been stuck for child care and she has refused to help. As a result both my dh and myself have had to take unplanned leave from work.
For example, today my dh rang her at lunch time to ask if she could look after ds tomorrow. He explained we are desperate. Dh has an interview up north tomorrow and I have no leave left to take. MIL does not work so is in theory flexible. Yet again she told my dh her social plans had to come first. She would not rebook her spa treatment in order to help us. She had a spa day last week also.
Am I unfair to feel this is a bit off?

OK, back to the OP.

YANBU to be disappointed.

But YABU to expect her to change her plans.

Would have been nice of her, & I think I would in her situation.

Just to clarify, as I didn't realise this would get a 5 page response. My employer would not allow unpaid leave as this requires 21 days notice. Bah humbug but that's just how it is. they make life hard whenever I take time off for childcare.
I would have happily had unpaid leave as my priority is ds.
It was an emergency as he was sent home from nursery with suspected conjunctivitis and told not to return for 48 hours even with drops.
The spa have a 24 hour cancellation policy with a full refund. But would have happily paid if no refund were given.
In the end it all turned out for the best ( other than my mil being a self absorbed individual). My dh had his interview and it went well. Fingers crossed that could be a fantastic opportunity for him. I went to work as got a note from the dr stating my son has a cold but not conjunctivitis. My ds went to nursery as planned.
Thanks all for your comments and yes, my sister is a busy but amazing star for offering to help xxxxx

I am glad it worked out for you tickle.

Oh good!

And as for next time - well you've said you spend time with her when you're there too so she just has to have fun, so it isn't that she is feeling used. She is, as you say, self-absorbed and likes the image of "grandma" more than the reality. I think your solution is to
a) stop asking for help
b) when she says that she wants to help, say "but whenever we asked you, you refused, so now we don't ask"
c) swallow your disappointment that she doesn't love you and your family quite as much as you'd like
d) move her down your priority list a bit. Like if it's a choice between spending time having fun with your sister or your MIL, you'll be choosing your sister, won't you? When your MIL wants you to parade your ds at some event of hers, you'll be a bit too busy ...

She doesn't want to do it but she likes the idea of being the doting and caring grandparent

My Mother was the same so we stopped asking and stopped running to her agenda

She still tells her friends how helpful she is and how she makes the difference between sink or swim

I had a very difficult time a while ago think separation long term hospitalisation of my baby etc she took 2 children to the park once for two hours and I've just remembered did look after my youngest again for a couple of hours whilst I went for a job interview last year

Still more than my sister in law and brother did and they live just down the road