I think you should advise him not to worry, the money received from airdrop is completely free and he should sell them as soon as he receives them.
As far as the holding is of a potential and profit promising asset, indeed the amount of reward will be more than satisfying. Patience and perseverance are two most important skills for becoming successful in any domain of life. This is not possible to achieve big without sacrificing big. Coming towards scams, they have become a pain in the neck and market is now full of such frauds. I also appreciate bitcoin trading for safest and success.
