I severely doubt that if it were a drug investigation, or a cop-killer ala Chris Dorner, the cell company would wait a billing cycle to provide location data.

I severely doubt that if it were a drug investigation, or a cop-killer ala Chris Dorner, the cell company would wait a billing cycle to provide location data. Notice also that nobody needs to file a subpoena. The cell companies can just hand it over, and often do. Because your brother is less important to the police than a drug dealer, they're not willing to blackmail the cell companies.