Let's justt say for the sake of the story Wally lived and he married Artemis.

" What happens when someone changes the future and you know it means his parents never meet and that's for a fact?" Bart asked looking at the screen concerned." Would he be able to live in the past? Hypothetical or what ever what happens?" Wally looked at Artemis trying to figure out what to say as Bart kept on talking not helping them figure out what to say. " Would another version or different person be born in his place living a better life then he could ever hope to dream about? Does he just vanish or croak? Does the mere memory of him just vanish and nothing is left? Does everything I or he accomplished just be forgotten and people live in bliss?" Bart's voice broke as he kept on talking. He was clearly scared. This wasn't just a random fear or thought

Wally West was really regretting having invited Bart over to watch a movie and was really feeling bad for choosing science fiction and a time travel movie. He felt so bad about how he unintentionally made Bart feel and how he was worried about his cousin once removed. " Bart w-we don't know at all. But I want to tell you that you've left impacts. You helped us the Team and the world and trust me you've left evidence of being here. Pictures, and trust me there's even videos of you. You can't just vanish they're always been something. Even if it's just a small nagging feeling."

Bart smiled at Wally brushing away a tear." That's crash Wally."