The guy has made a fairly large number of predictions of market crashes over the last few decades. He was right once, which was a big deal. But he has been wrong a lot of other times. Eventually, there will be another recession, and another market crash, and he will be right again.
In the long term, markets generally go up, though. Staying short for long periods of time is not advisable, and very costly.
Passive funds, such as index funds are the way to go. In finance, you get what you don't pay for - fund expense ratios and other transaction costs.