I didn't see mate in three but I saw after Rc8+ we're then grabbing the queen with check, stopping him reclaiming it with the fork. That's enough to win, and probably I find a mating pattern if I look for more than two seconds.

Lesson of the day is... if someone offers you the queen for "nothing", take some time to ask why he made that move. Was it really a blunder? Well in this case yes it was, but you replied with a worse blunder.

It's an interesting position for black, he's a piece up but he's not comfortably winning. His Qd4 was a blunder, but it's hard to find a good move for him instead though despite his advantage. He has big problems along the a1-h8 diagonal, but presumably with perfect play black can give up the rook for the bishop and maintain a marginal winning endgame advantage. Maybe white can force a draw though, idk.