Thought about this. Maybe, if they heard an voice downstairs and an argument, and they identified the person immediately as a friend of J. I could see the girls trying to get him to come help deal with it initially rather than calling 911. But the timeline of the calls seems way too long for that to me. Surely if it was escalating to audible violence, screaming, bodies thumping around, as it would have had to in that scenario, and he hadn't picked up in all that time and all those attempts, they would have tried someone else, or 911.