Please do note that you already have some information. I do not know from which part of India are you. Nevertheless, please do note that the Chartered Accountancy course, the Cost Accountancy Course (ICWA)l,or the Company Secretaryship course (ACS) , are all too good and your sister should compulsorily register for the first if she is really interested in becoming a Chartered Accountant. Kindly note that the 12 standard qualification itself is enough these days, to pursue these courses, details of which can be obtained from their respective websites.
You will do well to take your sister to a qualified Chartered Accountant, either having an independent practice or settled in a good organization in a senior position, so that she will get a more clear picture.
There are many Universities like the Christ University, Bangalore or the world-famous Loyola College, Chennai, where the B.C om standard itself is so high. Additionally, in the case of Christ University, Bangalore, there is a superb course, that is called Certified Institute of Management Accountants, called CIMA course. Your sister can join this course, immediately after joining the B.Com course. Similarly, the CMA course is also offered in some institutes, in Chennai. Please do note, CIMA and CMA are totally different two courses.
After B.Com, if your sister wants to go into Capital Markets, then the ideal course would be CFA. This is an American qualification, and the standards are very high. There is some private coaching in select cities, details of which can be had from famous colleges like Loyola College. Am told there is private coaching In New Delhi and Mumbai too.
The CBSE is a good platform for the UG studies. However, your sister can straightaway join the CA or the ICWA course and the correspondence course in B.Com, from either University of Madras or IGNOU or the Annamali University, which has centers throughout India, for the examination.
Now, the career prospects. Each of the aforesaid qualifications, on completion, will help your sister get a take home salary of at least fifty thousand at 2018 prices. Even manufacturing organizations like the TVS group start at 7.2 lakhs per annum and the training period is just one year. So, each of the aforesaid courses is simply superb.
However, one should always remember to gather the right kind of experience. Five years of accounting, should be followed by experience in Financial Management, handling the Initial Public Offer and things like that. Corporate Finance is also a vital part of the experience that she should possess.
Apart from these things, she should also take up an Executive MBA after three years of experience. Of course, after CA, if she can do her PGDM from one of the three main superb Indian Institutes of Management, at Ahmedabad, or Bangalore or Kolkatta, she will park herself in a superb career, where salaries of upwards of one crore rupees is possible within six years of hard core experience.
Another option is to gather four years of hard core experience as an executive and then join the Indian School of Business, Hyderabad or Mohali. But this one year PGDM, which is rated on par or even better than IIMs, comes at a huge cost and would involve taking the GMAT examination and getting a very high score.
Your sister can choose either of the above paths. Today, there are too many choices. All the very best.