Our four year old grandson has been physically hurt by his 4 year old cousin (much bigger). Hid mother won't do anything about it. Now our grandson is peeing behind his mothers couch to hide from his cousin. He doesn't do that at out house, his dad's house of school. His cousin has left bruises, contusions, rope burns on his arm and bite marks on him. What is our plan of action if his mother just ignores it as...its what kids do? Our grandson asks us if his cousin is trying to kill him.....this is very frightening.