First, behold what things gun control laws can be used for. (I.e. the police aren't the only people given power by bad laws.) Sort of like how the carry-on baggage of innocent people in Singapore can be slipped some drugs at an airport, and then the travelers subsequently face the death penalty when they are found.
Second, she should be charged for the crime she was framing him for, because he could have been jailed for a long time, not to mention forever losing his gun ownership rights. I think putting all those consequences back on her is only fair.
Third, think of how lucky this kid is that it happened in TX. In how many other jurisdictions (MA, CT, IL, CA, MD, NJ, MD, NY ... ) would the police have just arrested the kid, assuming he was guilty as charged, and without bothering to trace the call and pull the surveillance tape? I have to congratulate the police here for bothering to have the wherewithal needed to discover this ruse.
(And yes, MD was worth mentioning twice.)