^ You did not probably fully understand what is the function of BTC and how affects the price to become volatile.
Because BTC has a fixed amount and the price varied on the demand and supply in the market cap. Once the demand will increase, it means the supply becomes less which in turn to BTC becomes expensive and the price was pegged into a dollar-based value. Nevertheless, it is impossible that you mean BTC will become stable in price, the price will always be fluctuated due to massive traders of altcoins in BTC pairs.
Yups, the Bitcoin price will not continue to be stable. It is true what he said. Because the ups and downs of a currency must have certain causes. There is no way, the price of that currency will become stable. Maybe for a few days you can, but on the next day there will definitely be something that causes the price to decrease, whether it's from an economic or political situation it can cause the Bitcoin price to either slowly decline or immediately drop far from its usual price. Vice versa, this situation can also make currency prices improve and soar up, even exceeding the usual price. The price of crypto is basically influenced by its demand and availability in the market.
As an example :
The demand for bitcoin in the market is on the rise, but the availability of sellers is not able to meet the demands of buyers in the market. Thus, the price of bitcoin goes up, because demand is higher than availability. Likewise, when the market wants to melt bitcoin into cash and its availability floods the market. Thus, the price of bitcoins will fall, as there are more sales than purchases.