I would think that the technology for cryo freezing people would have been newish by 1999, so there probably aren’t too many people from before then who woke up in 3000. There may have been a few people who froze and unfroze around the same time, so he may not be THE oldest, but I think that he’s the oldest person in the series
Not only this but Bender also time loops hundreds of times (if not thousands) in the limestone cavern under Planet Express in Bender’s Big Score.