My wife and I asked my mum to come help with the babies and we would pay her as she would have to leave her volunteer job. We live 800km away and have no family here to help and my wife's family live on the other side of the world.
I asked her several times and offered a great wage but she just said "you don't have to pay me, I'd do it for free"
My reply "that's just it mum you don't do it for free and you won't do it if you are paid". She went quiet after that and I felt a little bitter.
When my kids have babies I really want to be there and help them.