with that $4000, he can get half of bitcoin and he can keep it for a long time before the price increase higher. but it depends on how long he can keep and he still has another option to buy the other coins. I think there are too many undervalued coins in the market but unfortunately, we don't know which one and it needs analysis and research to find one coin or more. the undervalued coin doesn't mean that the price is cheap but it could have an expensive price too because like we can see right now, ethereum and bch still undervalued but the price is too expensive for us. the cheap price doesn't guarantee for us to make a big profit in the long-term.