Maybe they're confused about his abilities because he didn't do well on the 2nd grade assessment. Do you know why he would have done poorly on that assessment, but well on the 3rd grade assessment? (maybe was there a subject on the 2nd grade test he hadn't seen yet, but would be able to learn quickly??)

Did the testing for giftedness have a math component that you could also use to support your point?

Sorry you're having trouble with this.