Investing btc is a very good decesion because your money will multiple.To the traders it is benificial to them to invest money.its the fastest way of a trading transactoin now.
He asked something else if you care to reach the actual topic and not just the heading of it.
We all know investment in bitcoins is a good choice but that is very risky too and he wants to know how to avoid that risk, I personally feel the same but then there is no solution too and if there are no price changes then there would be no fun too. Its like friction, necessary evil.
If there is no risk, then there will be no reward. Risk is a natural part of trading and investing. Risk to investing is like shadow to light. Its always going to be there whether you like it or not. You just have to manage your risk and keep it under your calculations.