He provided some statistics about the trading volume of some exchanges starting from the Decentralized exchanges having a total of $4.9bn 24 hours trading volume and Binance a centralized exchange has 4 times the entire 24hours trading volume of DEX with $16.7bn 24 hours trading volume with some other CEX like Okx with $4.7bn 24 hours trading volume.
Apples and oranges are being compared here.
For starters DEX usually has lower trading volume and if it is a true DEX you shouldn't even be able to know what its volume is because there is no central authority to be aware of trades and compute a sum of all trades!!!
The volume for Binance which I assumed was taken from CMC is the total Binance volume not bitcoin trading volume. That is vlume of bitcoin/tether, bitcoin/altcoin, altcoin/altcoin,... from hundreds of altcoin markets. When you are comparing volumes you should compare volume of a single market not all markets combined. Meaning only bitcoin/fiat markets. Which turns out Binance has a very small volume there.
Comparing Binance with 1654 markets with OKX with a much smaller number of markets is meaningless.
This comparison is also not taking into account the fake volume exchanges report since it is looking at total volume not per market.
It looks like your friend is just throwing numbers at you to make a conclusion that he likes.
His point that got me thinking is that if the regulators sanction the top 5 CEX for refusing to ban Russia the price of bitcoin can drop to 30k then down to 8k. Or even if they didn't sanction the CEX that the news about sanctioning them can as well drop the bitcoin price.
Cracking down on exchanges (regardless of their volume) can only cause temporary panic sell among newbies. What is clear here is that your friend is "wishing" for $8k because he was too scared to buy when price was that low and he is dreaming of those lost opportunities
So do you think that bad news about bitcoin affects the price of bitcoin? Using the example above if such a news arises about sanctioning the top 5 CEX will the price of bitcoin drop drastically?
News has always affected bitcoin price, the question is the degree which is not possible to predict because it depends on the degree of the news. For example they can't attack all bitcoin exchanges, they can only attack those in their own jurisdiction. For example US can attack Coinbase not Binance. It also depends on the "attack", are we talking about shutting down the exchange or just a slap on the wrist? Finally it depends on how the market manipulators run with the FUD and how weak hands react to it.
In summary your friend is either a newbie who doesn't understand the market and as I said he is just throwing numbers at you or he is a manipulator spreading FUD.