It wouldn't make sense anyway (Is he 53? would it make sense for a young vampire to be that age 20 years later? It would be weird), unless they used CGI to rejuvenate the actors (Angel and Spike?), or he was cured of vampirism living a human life with Buffy? which would be better suited for a cameo, I still think they'll reboot Buffy even if it takes a while. I don't think it will happen now because the series ended in the 2000s and it's about to complete 20 years away from the end, and at most it can gain strength to be restarted in about 10 years?, as there have been a lot of reboot cancellations at the moment. I confess I was curious about the last project being a sequel in the buffyverse, about a slayer being a black girl and a new scooby gang instead of an official reboot with a new buffy, I hope it works and doesn't fail like the Charmed reboot.