I am so pissed how much water can our 6 month olds have?

I read they can only have 2 oz all day. I found out her grandfather gave her 4 oz at once of just water without even asking me. 
She had an entire box of formula why the fuck he didn't give her formula I'll never understand. 
Is this okay? I'm a first time mom and I am so pissed and worried.