Are his print jobs taking a long time because he has to wait for other peoples' jobs to finish, or is his computer taking a long time to send the jobs to the printer?
If he is having to wait for other jobs to finish, you can set up a separate print queue on the server for him with a high priority and only give him permission to use it. The high priority will result in his jobs being printed before jobs from other users even if they are already queued to print.
If his computer is taking a long time to send the jobs to the printer, it may be that he is sending very large jobs, or jobs with large images that take a long time to render. Or he might just have a slow computer and/or network connection problems.
edit: In general I would say that you don't want to use the "print directly to printer" option when printing to a network printer. This could result in pages from multiple print jobs being mixed up in the output tray when other users send pages of their print jobs at the same time that his computer is sending individual pages to the printer.