I've honestly never seen that happen at the end of an NBA game and I've been watching a long time.
That idiocy should result in his immediate dismissal, but like others have mentioned, its probably better he ends the year with us so we can really get the tank rolling.
I cant believe how stupid he is. If he actually thought there was a 5 second differential, EVEN AFTER he called a timeout, then it's still horribly bad because of his ineptitude and lack of awareness. But if he didn't, and actually wanted to play it out with a 2 second differential hoping to get a rebound and last possession, then he's the worst coach in basketball history.
I didnt get to watch the game originally, but when I read what happened on twitter I couldnt believe it. Then I went on LP and watched it for myself and my jaw hit the floor. You can tell Henderson purposely took a rainbow jumper knowing the clock situation like any smart player would, knowing by the time the ball came off the rim the game would be over.
Rewatch the end, and look at Terrence Ross' reaction. It's quite funny.