I would make him a PG

He will be a nice PG with good secondaries. That potential is amazing too. I would get his passing up a bit and then work on big man skills some because it will help him in the long run. I do have a comment about your team though. You have WAAAAAY to many young players. You should try to keep 2-3 trainees and focuse your training around this player. Find the other 2 players that will train will him the easiest (Probably the shorter players 20 or younger) and sell all the other ones to get some more experience on your team and older players. If you do not have any other trainees that can be trained as a guard then sell all of them.
Murray/Harris/MPJ/Grant/Jokic - 2020 NBA Champs