Need help with 6.5 l diesel

A neighbor has a 1995 GMC 2500 6.5 liter. He has had the fuel filter clog and shut the engine down. He replaced the filter today(06/19/06) and cannot get it started even with ether(I know,it's not a good idea). There is plenty of fuel to the injector pump and injectors,engine turns over fine,etc. We were thinking it might have jumped time. If anyone has any ideas I would appreciate it. Neither one of us has ever seen a Diesel that wouldn't at least hit on ether.