He was at that school because he was too old to play according to LHSAA rules, but didn't have enough credits to graduate. That school let him finish his hs diploma and play ball.
My understanding is that he is 19, and he may be 20 by the time the season rolls around. Going the prep school route actually isn't all that uncommon these days for kids pretty serious about developing their game and for whatever reason haven't picked a school, have their birthday such that they aren't eligible for high school or just want some more seasoning and exposure. We actually luck out b/c we get a four-year kid who is more physically mature and seasoned.