Sure they do. If his real estate company closes a lower dollar volume of deals, because money that would’ve been going to sellers is now going to banks as interest, then its stock is likely to go down.
This is largely a zero-sum game: if the bank is taking more money out of the transaction, sellers (and their agents who work for a percentage of the selling price) will be taking less. It’s not like buyers can magically afford to pay the same principal as before plus new higher interest rates.