I had ED-E, I never did his quest, and then he died (he was dying all the time and I'd had enough so I didn't reload and figured I'd find a new friend)

Now, I'm doing the Hound Dog quest, but I can't have Rex come with me because the game still insists I have ED-E with me. And I don't. His perk is still on my perk list, but it's not doing anything for me anymore I don't think, but maybe it is, I can't really tell.

Do I have to find his body and tell him to take a hike, or is he maybe not dead, or is the game just screwed up (thus far I haven't had any major issues, just a couple freezes)

Thanks for any help.