Sounds like a good case for trial. Perhaps argue he wasn't aware the gun was there and that it belonged to someone else? Otherwise, if it's a first offense of unlawful possession of a firearm, the child would likely get a deferred contract. If he completes his community supervision successfully the case goes away. No record.
If it's the minor's first offense, the prosecution might suggest a deferred contract where he would have to fulfill specific terms of probation and once that is successfully completed the charges would be dismissed. You should contact your local Bar Association for a list of Juvenile Law attorneys in your area for representation.
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