Until the student is admitted, he needs to pursue all his options, just as the school is still looking at other athletes. Go and meet with the other school. Sounds like he’s been honest with the second school and everyone knows he’s just keeping his options open. Second school might be hoping to impress him and move into first place.
Many football players at the top D1 schools have 4-5 schools on their list right up to signing day (or later if they don’t sign).