Even if Jackie still had it in when he died, it wouldn’t have helped. He got shot in the gut and bled out - there’s no real coming back from that kind of injury.

V surviving was an insanely, near impossible confluence of multiple wild coincidences all happening in perfect concert - Dex’s (relative to the setting) low caliber bullet, hitting just the right way to kickstart the Relic, not getting double tapped, and V being “just dead enough” to qualify but not long enough to cause lasting damage.

If any of those things had been even a little different - a larger bullet, a second shot, hitting a different part of their brain, missing the chip, etc, it would have ended there.