How to stop mil from feeding baby water

My mil and my hubby has been feeding the baby water as she has a bit of jaundice. She is only 7 days old and I know that babies this young shouldn't even have water at all and I couldn't do anything to stop them from feeding her water. It really makes me worry alot if anything will happen to baby. Any other moms experiencing the same issue? How do I make them stop feeding her water? #firsttimemom #pleasehelp #advicepls