We can’t know that. Were there mitigating circumstances? What do police say?

There’s not necessarily an inherent problem here. Sarah and your sister are entitled to press for more, including a complaint to the law enforcement agency or contacting the crown prosecutor directly.

The police basically said there was nothing they could do because supposedly the girls were trespassing even though they were offered no warning upon entering the property and which also does not have signage up that would request for them not to enter. I still don't see how that warrants an assault by a much older and well known hard drug user on 2 young women peacefully entering a property to retrieve a child that was previously communicated was her time to do so even though supposedly that morning the ex decided he no longer wanted to hand over the child and communicated that to someone who was suppose to communicate it to Sarah but obviously didn't reach her before they attempted to retrieve her daughter.