My Wife and I recently (two and a half weeks ago) adopted two cats, a brother and sister around 7 years old, from our local shelter. On the first day, the brother was more confident, but then became very timid, and he keeps hiding behind the sofa and under tables. His sister, on the other hand, has been much more outgoing.
At first we thought this was just him being scared of the new environment, but recently we've noticed that she seems to be intimidating him - she'll come and push in if we are giving him attention, and she eats from his food bowl while he just sits and watches. In the last couple of days she's also tried to claim his favourite sleeping position (the back of the sofa), which would give her control of almost all the high-up places - she already has a cat-tree and the lounge window-sill.
What can we do to dissuade this behaviour? We're particularly worried about him eating properly, if she keeps stopping him, and we want him to be able to be more confident around the house and around us, e.g. being comfortable to sit on our laps without her interfering. - ideally we'd like them comfortable enough with each other being close enough that we can have one on each of our laps!
They are not yet allowed outside (it's only been just over two weeks), though we have, in the last few days, given them access to more of the house (hall/landing/stairs as well as the lounge and kitchen), and he's taken to sitting at the top of the stairs (claiming a new high-place?)
They currently have two litter-boxes, which, as far as we can tell, both appear to use. They have separate food bowls, but currently they are in the same corner of the kitchen. We have a three-level cat tree, and a separate scratching post (which he tends to use). We feed them wet food in the evening and dry in the morning, and he tends to eat more of the dry - she'll wolf down her portion of the wet food while he looks on from a few feet away, then move over and eat his...