He turns 18 the day the WC starts. If Dortmund are going to offer him a new contract they'll do so after this.
Not sure if leaving is the best option for him. No team better than Dortmund can offer him a starting spot. He might be better off signing a renewal with a sign on bonus or a sell on clause so that both he and Dortmund get something out of it.
Wouldn't mind having him as a gamble at Barcelona though. In dream land it would be a great transition from Lewy, but unfortunately we aren't in dream land.