His point on dollar cost averaging is sensible. Markets go up, more than down, overall [the statistically best approach] if you have a lump sum to invest the best strategy would be to invest it all now. There is added risk with this however, which he would accept. Also it doesn’t change the main reason people end up dollar cost averaging (by default, with retirement savings from each paycheck).
over long time horizons bonds are actually riskier than stocks… [also] there are more rolling 3 year periods where bonds lose money than there are where stocks lose money.
He discusses these ideas, and many more in his book: Debunkery: Learn It, Do It, and Profit from It-Seeing Through Wall Street’s Money-Killing Myths.
Related: Curious Cat investment books – Investment Risk Should be Evaluated as Part of a Portfolio, Rather than Risk of Each Individual Investment – Save Some of Each Raise