If the detective said "might not" and "possibly", he may not have been lying. That might have been his understanding of where things were headed and something changed. Even if he did lie, I'm not sure how it makes things worse for your son. He was given a lenient sentence on the first set of charges and is working on cleaning himself up. He's just going to have to deal with the other mess he made for himself. He was going to have to that anyway since the detective's alleged statements inferred there would be a charge of some kind.
There isn't anything you can do on this. It's up to your son's attorney.
I don't see why the deputy solicitor is getting pissy. He acted based on the information he had. He got a win either way. I also don't see how he figures the detectives statements in any way help your son.

