That's more of a *bawwll*.  I surely can listen 
and relate to that.

I'm afraid that, as at funerals, there's not much 
I can think of to say that would not seem trite 
and contrived.
  
We also live adjacent to wild property with 
coyotes and bears and mooses, and we have to 
watch the 4 cats carefully to make sure they 
don't sneak out, and I know from personal 
experience that I would feel very badly if I were 
in your place now.  Well, maybe I can say 
something, that's a little future-focussed.

There's no replacing a gone cat.  We still miss 
Boo Bear, our champagne Burmese, these many years 
later.  There was no replacing Boo Bear after 
what happened to him, but we honored his memory 
by asking Bubbito-chan (a Tonkinese kitten) to 
take over Boo's duties, and Bubby-chan has 
brought us a lot of his own kind of goodness.