Hi everyone... I'd like to ask - where is he? I cannot find him in the suites level, and I've told him to return to the lucky 38, when I was taking the ED-E... Where is the dog?

Same thing happened to me. Try looking at the King's place, that's where he was for me.

If the follower has not returned to the home base wait 72 game hours first for them to show up. If they don't, then go back to where you first met them. Or, try their home if you met them somewhere else, like you do with Veronica or Raul.

Thanks for the information.

He always goes off to King's for me - and when I enter the building, he always starts running towards Lucky 38, as he should.

I bad the same thing happen to me but when I went to the kings to find him he wasn't there.... I entered diog with the king and the only thing I could say was that Rex was dead..... Is it possible that he died... I'm not in hardcoe mode so I do t think that companions can die..... Who knows

Check the lounge inside Lucky 38.
I had heard they go there.

Companions return at a walk. Fast travel will beat them from any location on the map with time to spare.

I'll try the lounge.... I know they walk so I waited for 4 days and now I've just kept playing and it's been about 2 weeks game time

It happened to me with Lily. Turns out she hadn't barely even gotten to the strip yet and it had been 24 hours.

He's still going there, just taking a while and probably fighting enemies along the way.

Next time, fire them just outside the Lucky 38 or the elevator.

That's what I started doing.... Just easier now

From the Fallout http://fallout.wikia.com/wiki/Fallout:_New_Vegas_companions;

"While actively following you, permanent companions are treated as essential (unless you are playing on hardcoe Mode, see below). It is important to note that they are only essential when following you, and they can be killed both before they join you and after you tell them to leave."

So, yes, even if not playing on hardcoe the companions can die.

They can't get kill if you are not near them though.

But yeah, most of the time Rex would be in Kings'

Well that solves it... Wish I could find him he had some good stuff on him