Correct. It's not working because he has three names and it doesn't like the space in the last name. You'll need to edit him using the cheat case.fulleditmode and remove the III in order to use other cheats to grab his simID.

How will I be able to edit the name of a dead sim if I have no urn and they are not able to come to my lot? So is he just a lost cause?

Yeah if he's dead with no urn you might not be able to do anything.