I don't really understand what you are saying here, who got KDB for free? De Bruyne is not heading to Ac Milan, he is actually finalizing a move to Napoli, which should be settled very soon, except the deal falls through. As for Walker, he is back to City after a failed loan spell at Ac Milan, though City have decided that he is definitely for sale this summer and there is no way back for him into the team, so on that note, what were you saying about Milan getting these players?
The colleague may have mixed up the teams! Anyway: I think it's a shame that KDB is moving to Serie A, I think he should have moved to La Liga and would have fitted in very well at Barca or Real. Even better at Real, because they lack a real playmaker after Modric's departure and Kevin could have been a good replacement.
Nevertheless, I'm looking forward to seeing one of the best midfielders from the PL in another league and I wonder whether he'll find it much easier there?