The answer is no. Nothing you do before the heist or during the mission can save Jackie Welles. No matter how safe you are or what choices you make, Jackie will die in the backseat of the Delamain. Games don't often kill off such prominent characters in the early stages of the game, but Cyberpunk 2077 isn't normal.

Is there a way to keep Jackie alive?

Despite your love for the character it is not possible to save Jackie in Cyberpunk 2077. It doesn't matter what you do leading up to The Heist mission, the ultimate fate of Jackie Welles is a core part of the story and cannot be avoided.

Can you prevent Jackie from dying?

Unfortunately, there is no way to prevent him from dying in the seat next to you, as he passes away when you reach the rendezvous. The only real decision you have when it comes to Jackie's death is what Delamain does with his body.