I'm new to this site and am so delighted to see a post about Havana Browns!! I lost my Havana, Chile a couple of weeks ago and our vet said that she was so sad because they seem to have gone out of favour. Crazy - I would choose Havana over any breed!!
I've had two Havanas now, and would have another in an instant. Chile was my best friend for 10 years - a beautiful kitty and a real mummy's girl. She was incredibly attentive and tremendous fun.
Here's the catch though - Havanas are extremely intelligent, attentive and need a lot of love. They're very vocal, and like to be the centre of attention! If your sister is looking for a laid back cat then a Havana is not the breed to choose. If she has the time to devote to a 'dog like' kitty companion, then I would recommend a Havana Brown every time!!