The villain here doesn't have to have anything to take this line. Sometimes this is ATC, more times its a big
or big
+ pair.
If you take the line b/b/b and the board pairs, you will hear from the set become FH somewhere in there.
Next time if you want to see his hand... Remember you called him, and in most rooms that means he has to show first. Just look at him and say "So what ya got?". If the situation gets tense or drawn out just add "I have the nut flush" (while tabling your hand) and let him muck his junk without embarrassment.