I'm going to wash my kid brother in the same water I use to give my dog a flea bath.
That's gross. Why would you do such a thing?
My brother likes to bathe and we can get rid of any extra fleas at the same time.
It is wrong to bathe a child in dirty dog water. The flea medication might make them sick or injure them.
It's mostly only water, what's the problem with that?
But it is not only water, the medication that is in flea shampoo that you used on the dog is also in the water. You could make your kid sick by not using clean water to give him a bath.