Hahaaha unbelievable bullshit. Tell your friend to stop watching football.
Players are individuals, teams is unique. Some teams just crumble under pressure and Napoli surely was one. They were nervous, they feared to make mistakes. They feared to attack (to leave the defence exposed). That's human. That's not some great betting (or politics, wtf) conspiracy. They didn't have a good game plan to contain Verona's wings so they had huge problems on the wings (specially left wing) in the first half which clearly some kind of paralyzed them. Gattuso didn't do his job properly in that match.
And of course, Insigne the biggest chokers or all chokers, did what he always do. Choked.