Hi, I'm looking after my friends 8 month old baby over night. I've only ever had her on my own during the day once before.
She won't drink her bottle of milk, she takes tiny sips then refuses, or just refuses. She's been crying and wouldn't settle. I've been doing all the things her mum told me, I was lying next to her on the bed, rubbing her back etc. It came to a point, I had to go to the loo so I had to just put her in the cot and leave her for a moment. I notced that she was calming down without me there, so I left her a bit longer and she's now sound asleep.
Her mum says she sleeps through the night, but because she hasn't had her milk she might wake up now.
What should I do if she wakes up and still won't drink her milk and keeps crying? 
I gave her two of her biscuits and some watered down orange juce, she drank far more of that than she would the milk. I'm not sure if that was the right thing to do, but at least she won't be hungry or thirsty for a while.
I don't think I'll offer to have her over night again if she dosn't sleep through all night.