It is quite common for Indian students to study medicine in Kyrgyzstan (Bishkek) I would say, certainly far more common than in Kazakhstan.
Their visa system is probably more friendly as would be the weather, especially if you are coming from either the middle or south of India.
In Kazakhstan, depending upon the city, the temperature can range from -55C in winter to greater than +40C in summer. Whilst heating and double glazing in most buildings helps with the cold, airconditioning in the summer is not common.
The cost of living in one of the main cities in Kazakhstan that have a medical university, would be higher than if she were to be studying in Bishkek.
The traditional diet in Kazakhstan depends heavily upon meat and bread (or grain based foods, noodles et cetera) with little reliance on vegetables.
There are foods with quite some eastern European influence, but this also depends on what city she would come to.
You can, of course, obtain vegetables, but they may not be quite the same quality and variety she may be used to.
Many students in Kazakhstan, especially for qualifications such as medicine, prefer to go to universities in Russia, such as the medical university in Barnaul, which is quite highly regarded.
English is not widely spoken in Kazakhstan, so student life, mixing with native Kazakh and east European descendents, would probably be a little difficult unless your sister has a good grasp of Russian or there are enough students from other countries that speak English or her native tongue.
Medical care here is not yet at first world standards ... the rich prefer to go to other countries ... the poor have to put up with a less than optimal health service and spend a lot of their time in pharmacies, there are far more pharmacies than would be regarded as healthy ...