2 reasons he WON'T be fired
1 - there is no replacement
2 - Pat Riley doesn't want to have to coach again
When the Heat miss the Finals this year, he'll be asked to resign this summer. Then Riley will target either Doc or Phil, neither of which will accept.
As for current options, there's Sloan,Jeff Van Gundy and Mike Brown HAHA. Sloan would be BEST, but noway that happens...