My moms still giving my daughter a bottle?

We got Aaliyah(19 months) completly off the bottle and pacifier by 14 months, It was living hell for a week, Now she uses her sippy cup and never asks for a bottle...My moms starting to watch her during the day from 11-2:30 and she has bottles at her house for my nephew and she gave Aaliyah one because "it wasn't fair that Tyler got one and Aaliyah never." Tylers at my house all the time and Aaliyah never cries when he gets one or tries taking it. We've told her Ty's a baby so he gets a bottle but shes a big girl so she uses her sippy, and shes fine with it. Now she keeps asking for her bottle and cries when we tell her no...Shes laying next to me crying and kicking because she wants a bottle...I asked my mom not to give her one and she said its not going to hurt her to have a bottle when she wants one and if we don't give her one here then she'll get use to just having one when she goes there and will look forward to going there...I don't want to send her to daycare but i don't want to fight her all over again to get rid of the bottle...How do i get my mom to not give Aaliyah a bottle? We send sippys over there and i know my mom has sippys that Aaliyah's left over there before.