Beer doesn't "die," and an airlock is just a vent, it's not a fermentation gauge. What happen was after you pitched yeast and put the lid on the fermenter, the oxygen that was in there before put your beer in, and probably added more oxygen by aerating, or shaking or whatever, needed to come out, and the airlock did what is was supposed to do. Let it out...your beer wasn't fermenting, your fermenter was OFF GASSING. Now nothing is happen in your airlock, because the yeast is reproducing now before it starts eating the sugar...that can take 72 hours for yeast to get going.
Once it gets going it may or may not bubble again. Bubbling doesn't really mean anything other than the airlock is bubbling. And airlock is not a fermentation gauge, it's a vent to bleed off EXCESS gas, be it oxygen or EXCESS co2. It shouldn't be looked at as anything else, because an airlock can bubble or stop bubbling for whatever reasons, including a change in temperature (gas expands and contracts depending on ambient temps) changes in barometric pressure (You can have bubbling or suckback in the airlock, depending on pressure on the fermenter) whether or not a truck is going by on the street, the vacuum cleaner is running, or your dog is trying to have sex with the fermenter. Or co2 can get out around the lid of the bucket or the bung...it doesn't matter how the co2 gets out, just that it is.
And bubbles don't coordinate with anything concrete withing the fermenter, "x bubbles/y minute" does NOT TRANSLATE to any numerical change in gravity....if an instructions says do something when bubbles do something per something, throw the instructions out.
Fermentation is not always dynamic, just because you can't see what's going on, doesn't mean nothing is going on. And just because your airlock starts up, and then slows down or stops in a few days, doesn't mean fermentation is over YET, it just means the excess co2 is not coming out of the airlock...not that the yeast is done.
The only way to know how your beer is doing is to take a hydrometer reading, if you're worried. But not until 72 hours have gone by. Then if you're still concerned, take one...then you'll know.
But don't try to discern what the yeast is doing by what the airlock is or isn't doing. All it is is a cheap piece of plastic, not a calibrated gauge of anything.
