I took in my fathers 16yr old cat upon his passing this past Sept..

I initially sequestered her in the master bedroom which had been frequented
by the other cats in the household (four in all).

When she showed an interest in what was beyond the door; I put up a baby
gate in the doorway. She isn't fond of jumping, but the other cats jump the
gate on occasion. She just scooted into her travel cage where she felt safe.

She always spends the nights with me, the bedroom door being left wide open.
I am some times awakened by the verbal negotiations of who is permitted to
share the bed (seemingly her private domain)

She seemed reticent to explore the rest of the house, but has overcome that
by degrees. There is no need to share a sunny spot, a food or water dish, or
even a litter box unless she chooses too.

The other cats initially made overtures, but seemed to relax when they
realized that there would be no change in the status quo(transient furry
boarders are quite common). It's as if they realized she was older, and
liked her naps.

She isn't interested in becoming involved in their conflicts, and only talks
to them in passing.

But she's pretty quick to take advantage of their absence outdoors to help
herself to any available tidbits.

Its amazing how adaptable an older animal can be when given an opportunity.

Read "Ugly, the cat" posted 3.9 at 10:17.    Maybe the company will
make him feel young again.  Best wishes.

I took in a 16 yr old cat a few years ago, and he lived to be 23. Smokey was
a lot of fun and a good companion to my other cat. And he didn't have any
health problems.
K