My brother and his wife both work full time, they have one child in nursery three days a week and other child full time school who is same age as my DD.
The children are look after by other people, nursery, or before and after school club. I also help out one day a week. I volunteered to do this and I'm happy to do it 
I also work, but school hours so can drop off and pick up my child. I think most working parents worry about the school hols and childcare as there are a lot to cover.
My SIL is lovely and we get on really well, we try to work the hols out between us, however next week is a problem. I couldn't take leave as too many people are off, I've got four days covered but need one day covered.
My brother is off on that day, he is looking after his school age child but is refusing to have my DD saying he can't cope with the two of them! 
He doesn't think he should have to use his annual leave to cover the school holidays and will take a week off in the school term and just do his own thing, no drop off/pick ups and youngest still goes to nursery!
I've tried to explain it will be an easy day for him, they play lovely together, both good kids and all he has to do is supervise and feed them!
It really upsets me that he gets to lord it with his own leave, while his wife and I have to use all ours for school holidays, he gets more than me and all I'm asking for this half term is one day.
She won't discuss it because he has a hot head and it will all end up in a big argument. Everyone tip toes around him because of how he gets, he does nothing in the house, no childcare, no homework, no nappies, no bathing, in fact nothing! But to the outside he is the doting father
So should I withdraw all my 'goodwill' or just suck it up and sort something else out, I'm not being unreasonable am I .....