I can relate to you. My mum has always put my older sister first, and there has never been any explanation why. I'm currently pregnant with my first baby and i told my mum at about 6 weeks, and i have not heard from her once since i told her. I've been so sick with the pregnancy and hospitalised 7 times, not been anywhere but in bed or hospital since 6 weeks. I don't even know if my mum knows, I really could have used her help or support. My plan is to never ask her for anything, that way she can't let me down. I know you said you're looking for someone to look aftr your children in evenings or weekends and that can be difficult, but people get by without the help of their mothers, and she sounds so unreliable for you - even if she manages to be reliable for your sister. Some mothers are just like that, and it sucks. I'm sorry you have to experience this. Xox