Goody Ouchless No Slip Hair Ties, 10 Ct, Black, 4MM Rubber Bands, SlideProof, Pain-Free Styling Accessories for Women & Men, Made for Long-Lasting Braids, Ponytails & More, All Hair Types

For the problem with hair ties slipping off her head, Goodies makes a hair tie that has a thin band of silicone coiled all the way around the hair tie. It's the only thing I've found that actually stays in place. They also don't stretch out with use nearly as fast as regular hair ties. Goodies Ouchless No Slip Hairties on Amazon