Considering the fact that franchise insiders have talked about giving the main series a proper conclusion with the upcoming releases of Fast and Furious 9 and Fast and Furious 10, it would make sense to include Brian in that process and cap things off with a hero who started it all.
So, it doesn’t necessarily sound like Caleb Walker wants to bring Brian O’Conner back for a full-fledged starring role in one of the upcoming Fast and Furious films.
That said, based on his remarks, it sounds like he thinks Brian could pop in some capacity to help “save the day,” and presumably help get his friends out of trouble.