While I still have 5 dogs, my blind dog Lynch was close to Phantom, not that they played, but they tended to stay in the same room and they ate together etc. Since Phantom has been gone, I have noticed that he rarely stays in the bedroom anymore (he and Phantom used to hang out there during the day) and stays a little closer to me now. He also is whining at dinner time, and that's something new, I figured it was because he can't finish Phantom's food anymore.
I kept the routine up and just give him a bit more love and attention than he used to get/require. Some dogs seem to be needier than others and he's needier than he used to be. But then Lynch needs his seeing eye buddy and this is the second one he's lost.
Give Cougar a smooch from me and my hounds. He's going to do ok, dogs seem to adjust better than we do to loss (as well as other things too.)