When Paul Walker died during the filming of Furious 7 it understandably caused an outpouring of grief from fans and the co-stars he had worked with for years. Universal, Vin Diesel, and director James Wan gave his character Brian O'Conner the sendoff he deserved, allowing him to literally drive off into the sunset rather than killing him off which would have been terribly painful. Or perhaps it was just foresight on Diesel's part? Comments by Walker's brothers, who helped complete his unfinished scenes, suggest Diesel is looking for a way to bring O'Conner back.
Walker siblings Cody and Caleb made the statements to Entertainment Tonight while discussing Paul's legacy and the charity they founded in his name...
“I had a phone call with Vin for about an hour and we really discussed this a while back. He wanted [our] blessing,” Caleb said, adding that Diesel asked if and when they thought it “would be acceptable to maybe bring Paul’s character back… to really kind of let his fans know he’s still out there.”
“Universal wants to make sure to be respectful of Paul and his image too, and his family,” Cody added.
It wouldn't be anything more than a cameo and would use the brothers to stand-in for Paul, just as they did before with a little CGI help. This still sounds like an idea better left in the thought bubble. What could there possibly be for O'Conner to add to the story in a simple cameo, short of him being killed off? Honestly, Universal has kind of boxed themselves in this corner by including Jordana Brewster in the Fast 8 cast, since she plays O'Conner's wife. Why would she be involved but O'Conner not?
The best idea is to not mention O'Conner at all, but failing that they could simply have other characters make mention of him.
"Hey, how's Brian?"
"He's investigating things on his end."
"That guy still owes me a race."
I don't know, my screenwriting sucks but you get the point. Fast 8 opens April 14th 2017, hopefully with no CGI Paul Walker appearances.