Your sister probably suffered a little brain damage when she got pneumonia at age one. The combination of slowness, and unsuitable gestures etc suggests that. Perhaps you could consult a doctor, who may advise you, but there is no point in spending a lot of money to get a diagnosis that in a sense, you already have. I do not know where you live, so I find it difficult to direct you to any specific institution. From my experience, voluntary organisations that run programmes for children with disabilities are more accessible (and better at helping to develop a schedule of activities) than even the best doctors. Any doctor that you consult is likely to depend on a large number of expensive investigations, which may even locate the origin of the problem. But what you want is some good advice on treatment in everyday life. If you are in Chennai, for example, I would direct you to Vidya Sagar in Kotturpuram, which is a school for spastic children, who have had brain damage. They would normally only test children, but would, I am sure be kind human beings and help you to with some advice on the next step. There seems to be only a distant chance of your sister improving in health, but it is possible to make her behaviour more acceptable, through the right kind of counselling and behaviour modification. Perhaps a Clinic set up by a psychologist would be worth a visit.