I think that's a bit harsh on the young lad. It's probably just dawning on him he's leaving his childhood club where he plays with all his mates and his friends and family can come watch him week in week out.
He'll be coming to a new country, have to learn a new language, eat new food, in the constant sideways rain, what if he flops? what if he isn't good enough? what if he gets homesick? What if its not the right move at the right time for him?
Yeah he'll be earning a **** tonne of money comparatively and be able to support his family for the rest of his life if it goes well and he gets a bigger contract or a bigger club, but its a huge amount of change for a young lad who's probably never ventured outside his favela apart from matches, and a huge amount of pressure.
Football (or any sports) teams are like a family to those involved in them and it cuts deep when you leave it behind even if you are going on to bigger and better things.