Pedialyte!!?!?

Okay I'm not one to judge anyone on parenting. But my brother and his girlfriend have an 8 month old daughter. She's so sweet and cute, I love her. I haven't said anything to my brother because I don't want him to get offended and I don't want him to feel any type of way, But him and his gf give her Pedialyte in substitute for juice. She drinks it every day in between formula feedings. Like several bottles a day. I know it's supposed to be replenishing when your baby is sick, vomitting and or diarrhea. But I don't know if it could be too much? It has vitamins and minerals in it and too much of anything has to be unhealthy. Has anyone else done this? Is this okay? And no she's not sick. He gives it to her as just a drink. I just want her to be healthy and all, her Dr did not advise this either. Idk why they started doing it.