Sorry, not sure if the title is entirely clear!
My parents are getting two 2 month old kittens at the beginning of July. Today, they have ended up adopting an older cat (around 7 years old we think) in a bit of an emergency situation. This cat (Kitty) is probably more than a little traumatised as she has been separated from her littermate and old owners and moved to a new home very suddenly. Kitty is currently in hiding behind a bookcase and doesn't seem likely to come out anytime soon.
My question is basically, how should they deal with introducing these new kittens in a couple of weeks time? Although they've owned cats before they have been single cats, and they've had them from kittens, so both rehoming an older cat and introducing new kittens isn't something they've dealt with.
Any advice/tips/ideas very welcome!