If the mother had said that she thought her son was traveling across state lines to do a drug deal, would the police have done more?

You're confused buddy. I'm not blaming them for not stopping this crime. I'm pointing out that the police do not even try to prevent crimes from happening. They operate on catch and capture. Preventing crime is literally not in their job description or more importantly within the things they have a legal duty to do.

I'm sure the mom did miss things. Still she picked up on it in time to stop the crime from happening and made the appropriate phone calls. The police just didn't care because it's not their problem.