There is no magic formula. He might not be scamming but his snakeoil ain't gonna make anyone but him richer.
I do know the secret though to untold wealth:
Buy and HODL! Works everytime.
Past performance does not guarantee future results.
Anyway, it seems it's the wisest strategy, I mean in 2013 you had to have balls to do it.
It's 2019 if you have doubts about holding Bitcoin probably this is not your thing.