Please is there any difference between bitcoin and bitcoin cash?
As its already explained at your level but let me tell you one thing that don't invest in any of the mentioned coins because non of them are stable and you will lose your money.
Let us give him freedom to invest.
DYOR (Do Your Own Research) is our concern for him to avoid scam tokens.
Actually, as long as the token is not stable coin. It is subject to volatility.