juice/water for breastfed baby

So I'm a little upset I'm currently in the hospital recovering from surgery and my mother and sister are taking care of my 6 month old who eats solids once a day and drinks nothing but breastmilk ... they came to visit me yesterday and she had one cup filled with apple juice and a cup of water ... do breastfed babies need water or juice? What nutritional value if any does it have ? I asked my mom why did she give her juice and she said I'm sure she's tired of just breastmilk 😑