It's been proven that Humans use all of their brains. The "10%" thing came from experiments where 90% of rats brains were removed and they survived, but they were no longer able to perform complex tasks and remembered behaviours such as remembering where to find food
I think your mother might have outdated facts, because from what I've heard and learnt that's not true at all (and trust me, I spend a lot of time on researching psychology AND visited a psychologist regularly for a year and a half. She told me a lot about the brain).
Even when you're asleep, more than 10% of your brain is used.
There are many instances of them helping humans
Believe me I have a biology teacher as mom :p
wait was that sarcasm
Even when you're asleep, more than 10% of your brain is used.