Never see him too much, besides heard about him in the last years. Palmeiras didn't use him too much as starter, what usually would be a bad sinal, BUT Palmeiras won Libertadores and Brazilian National Cup last year, so was a victorious team. I remember watch some good matches of him, sounds to me as a younger Gabriel Jesus (and he is from the same team).
It is a good bet on Brazil, but probably a little expensive because Palmeiras situation about money and titles are good.
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Looks like he have a poor, but really supporter family. A beautiful story about they believe and bet in his son to make tests in São Paulo state here in Brazil. No story about make bad things, looks like a good kid.
About this I would not have fear. Juventus have some old Santos players (Danilo and Alecsandro) to help him adapt too.
PS: If a young boy make 50 goals in our weak league, he would be selled buy at least 70 mi euros, maybe 100 mi euros. Neymar best score for instance was 17 goals, Romario in all his carreer never did more than 25 (young or old Romario), to give two examples. It is a bad league in comparation of top european ones, but it is not so bad. And most of the team play in defensive way, so it is not common someone have so much goals.