If you are looking for someone who dumped Forex trading for crypto trading, then search no more, you found one here, and if I must be sincere with you, i don't trade frequently anymore, but I enjoyed and still enjoy crypto trading much more than I did with Forex trading.
And yeah, it is very easier to make more money in forex if you are really good, but then is only because Forex trading is a multi trillion dollar market where as crypto is still struggling to become stable at its current market cap of billions, liquidity is never an issue in Forex trading, but liquidity is something the crypto market is yet to really achieve..
In the future, crypto trading will become the biggest in the money market, but before this can be achieved, we need adoption, and a market cap as big as how big the Forex market currently is.
Depending on personal preference. I also have a friend who has been trading forex for over 10 years, but he has no interest in crypto trading and hates it. He said that cryptocurrencies are too small and price manipulation makes it impossible for him to do any accurate analysis, but with forex, the manipulation is less and more dependent on supply and demand, so analysis becomes simpler. That's what he shared with me and I find what he said makes sense. The forex and stock markets are huge, I really don't think cryptocurrencies will overtake those two markets anytime soon.
Compared to the forex market all markets seem small, so this is not a problem exclusive of this market, with that being said it is true the manipulation this market can go through can be very intense, however that volatility can be deal with by reducing your position size.
But at the end of the day if your friend does not like to trade cryptocurrencies then he is free to avoid this market, however there is no doubt either he is missing a great deal of potential profits by taking that decision.