How long does it take for cats to get used to each other?
About two weeks ago I had to have one of my 9 year old cats put to sleep. It was a difficult thing but ultimately an easy decision (late stage kidney failure among other things). My remaining cat, his brother, has been seeming to be lonely and bored without him, particularly when I'm gone in the events (I live alone. I'm gone from 5:30am - 6pm every work day, out 1-3 evenings a week.). I have some friends that have been trying to find a home for their cats since the birth of their second daughter (two kids under 3, dog, two cats, both working). So I said I'd take Mars, their 3 year old, on a trial basis with the hopes that he would be a good companion for Doc. Mars was dropped off this afternoon.
There have been no open hostilities yet, fortunately although neither cat is thrilled about either. Mars has camped out under the couch. Doc is wary but willing to hang out with me in other rooms. Any ideas on how to help the two of them adapt to each other other than just waiting it out?