He's right.
The current M2 money supply: $14317.60 billion
https://tradingeconomics.com/united-states/money-supply-m2
US gold inventory: 258,641,878 oz
https://www.fiscal.treasury.gov/reports-statements/gold-report/current.html
Current gold price: $1280/oz
https://www.kitco.com/charts/livegold.html
So, 258,641,878 × 1280 = $331,061,603,840 worth of gold.
14317.60B / 331.06B = 43.25.
We would need 43 times as much gold as we have now to go back to a gold standard, or else we'd give the gold holders a MASSIVE windfall they don't deserve at the expense of every one else. Not gonna happen (sorry, guys).