Hi! I don't like to give 'advice' as what I do may not necessarily be the 'right' way but always happy to share my experience!
My DS is now 13 months. We've given water in a sippy from about 5 months I think, it took a while for him to actually drink from it, and then a little while longer for him to feed himself from it. He has water with his meals in his sippy (and throughout the day if/when he needs it), but we still give milk in bottles.
I may transfer to a sippy for his morning milk soon, not sure yet. But, in my opinion, your LO should still be given milk in bottles, it's a comfort thing more than anything I think.
HTH! x