lost cat found

Question
Hi Norman,
I had 2 cats, that are brothers and had been together for 3 + years, until we moved home, one of them got out the window before getting to know his new home and got lost. After 4 months, I was asked to take in an orphan kitten as he needed a new home. My older cat hated him at 1st but they get on OK now, apart from the odd slap and scuffle now and then, but in general they are ok with each other. Suddenly the other day, someone found my other cat in the local area wondering around after nearly a year, they took him to the vets and the chip in his neck and my lost cat poster had him sent back to me.
Now I have brought him home and followed your guide of putting him in his own room with food water and litter tray, and on Monday he's due to be re-introduced to his brother and the new kitten (now nearly 1 year old)
I'm worried about Harry (the brother that's always been here) as he's hissing at everyone and gets really Grumpy even with me and my partner. Is that normal, or is this all stressing him out too much? are we asking to much of him to accept another cat again?
Thanks

Laws

Answer
Laura,

It should be OK.  The dynamics will change, and Harry will be the dominant cat.  The hissing and spitting will go on for a while, but this too should pass in a few weeks.

I would try to give your established 2 cats lots of extra attention and special treats now and during the introduction period.

There are never guarantees, but, given that they got along once, the odds should be in your favor.  I would expect the brother to be at the bottom of the pecking order, initially.

Best regards... Norm.