Recently I had to explain to a friend what I was focusing in on financially speaking and I brought up crypto, specifically bitcoin. He was confused at first because he heard that it was unstable and risky. I knew that he already has a bad image of bitcoin so there was an urge to defend bitcoin but in the end I did not.
Your friend did not see any bad image of bitcoin; what he thinks is real and true. Of course, bitcoin investment is risky, and also the market is unstable (volatility). He heard that the market is very volatile, and there is also a risk that is attached to bitcoin investment.
But still, you can defend this because, to me, it is just something simple that everybody knows about bitcoin. You can simply educate him on how to come over these two things he thinks can stop him from investing in bitcoin. You just have to let him know that in every investment there is risk, and one must take risk before being successful in a bitcoin investment.
So to me, this is a normal thing that he knows and happens in the crypto space. Also, let him know about the instability of the market, which is the nature of the cryptocurrency market that no one controls. Operating on its own and investing for a long time will make him money after holding for a long time, so he should have no fear about that.