Cat behavior after the death of cat sibling

Question
I just buried one of my fur babies (Betsy) on Friday (the 13th, no less).  She was 13.  My question is about my 14 year old male (Monster) I still have.  Should I expect to see any mourning behavior from him and if so, what might I see?  Also, Monster and Betsy have been together for 13 years and now Monster does not have another cat around.  I would like to get another baby in a few weeks (we don't have real children) but I don't know what that will do to Monster.  Any suggestions or help from anyone who might have gone through this themselves?  And if I do get another baby- any suggestions on introducing him or her to Monster.  Full of sorrow and confusion and would love some feedback-- thanks!!

Answer
what you might see is him not eating as much or sleeping all the time and wanting/not wanting attention and if he has toys not showing any intrest in them at all. If you did get a baby cat I would introduce it as quick as you can so they can get used to being around each other plus he might take to it quick because its another cat but he also might not

keep me updated

katey