"Honestly? Not much. Does make it harder to take him down nonlethally if it came to it, but by the time he's using bloodbending to stop me from preventing him from murdering people, that wouldn't be much of a priority anymore. You'll forgive me if I don't name all my tricks out loud and give him a chance to think up counter-strategies, but I think I've taught you enough for you to realize I might have some."

Enough firebreathing control to warm a cup of tea, say. A solid enough theoretical understanding of firebending to make any flame he pleases out of any movement. The capacity to produce lightning, including with unusual movement patterns. It does not boggle the mind to imagine he might be able to throw lightning even while being bloodbent.