"Inflation is a quantitative measure of the rate at which the average price level of a basket of selected goods and services in an economy increases over a period of time. It is the constant rise in the general level of prices where a unit of currency buys less than it did in prior periods"

https://www.investopedia.com/terms/i/inflation.asp

If you think he's using some alternative definition then you'll need to explain how silver protects against it.