There is a set play book for how dealers react in certain situations in 3-card brag online.
First off, they only play if their hand includes a Queen high or higher.
When their hand is lower than that, you get a refund and you can play again.
If it’s the dealer does play, then you’ve got to decide what to do. You can fold or keep playing until showdown.
If there’s a draw, you get your money back. If you lose, all your money is gone. And if you happen to win, then you get the play bets and antes.