<p>The last we saw of baby Kelly, he was alive. Z was using him as bait for the stick, he can't do that if he's dead. Nick was destraught enough with grief having lost his friends and Adalind, if he lost his son, he'd want to kill Z. He went all commando, killing BC minions when Adalind took Kelly to the mansion I don't see him acting any different when he thinks his son is actually dead. He wouldn't be too rational enough to do anything other than finding an outlest for his grief AND rage and if baby Kelly had died, we would have seen it or have been told about it before Nick confronted Z the last time. Nothing ever happes off screen on this show except whatever took place in the twenty year time jump.
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