Noah had been told for years not to trust his mother's judgment when it came to Sylar. She herself had told him that she would defend him, be just as loyal to him as she was to Gabriel, and that Noah wasn't to take her opinion into consideration when dealing with the monster that wore his father's face. And, had this been any other situation, that advice would have been spot-on and taken to heart. However, there were several factors in this scenario and, fortunately, Noah was able to sort through them in his mind no matter how upset and tense he might be.
First was the fact that he knew from personal experience just how real the hallucinations could seem. He knew how all-encompassing that fear and grief could be. He also knew that this version of Sylar was not the monster that he'd been raised hearing about, and that the man clearly was caught up in remorse and wasn't on some bloody rampage of his own doing.
Granted, none of these thoughts stopped the teenager from grabbing the gun that his mother, although unbeknown to him, had disassembled earlier. Nor did they stop him from putting the gun back together with a practiced hand as he eyed the situation unraveling with a wary expression. The understanding that this wasn't a typical situation did keep him from taking aim the second he had a clear shot, though.
And the fact that Sylar had called him Bennet certainly helped in that regard as well.
So rather than take the shot being offered to him, he instead lowered the gun and gave a shake of his head. "No," he said in a soft, flat tone. "I'm not going to kill you." Taking a step forward, then another, and another, until finally he was alongside his mother, he added, "I'm not Bennet, either. I'm Noah. Your son... and I'm not afraid anymore."
Peering around the room, at whatever entity that was still out of sight yet he knew had to be floating around, he continued with a voice that was hardened like steel. "I don't know who you are or why you're doing this, but I'm not going to let you use him like this. If I have to negate every ability he has, I will, but he's not going to hurt us."
After a brief pause, Noah tossed out in a downright dangerous tone, "And if I have to get Emma in here to kick your ass, well, I'll do that too."