2 cats- female and sisters requiring an forever home

Hi
From my work colleague Sharlene:-
"I am hoping you may be able to help. My elderly mother has two tortoise shell adult cats; both spayed females (approx. 11 years old) and they are sisters, so need to go together. They are named Fluffy (because she is beautifully fluffy) and Mischief. They are fairly timid, (a little) anxious and undersocialised, they are house cats and use litter trays (although one has issues sometimes and goes besides the tray) – my mother does take them outside every day, but they predominantly stay inside (she and my late father have had them since they were kittens and they never let them outside because of the busy road they live on). My mother has health issues and unfortunately she is unable to care for the cats anymore. I unfortunately am unable to take on the cats as my landlord won’t allow animals and my brother has dogs.
We are against putting them down as they still have a life to live but are not sure what to do."
PS both cats are in good health