Deepa,
You should establish whether your cousin's MDS is classified as low-risk, intermediate-risk, or high-risk. The recommended treatment approaches differ depending on this measure of risk. Long-term dependence on transfusions is not a good approach for someone so young, but can be used to maintain her blood counts in the short term. There are drugs for MDS, typically used for higher-risk patients. The choices depend in part on which drugs are available in India. We know that ATG is available, so you might want to look for articles about ATG treatment for MDS, for example
this article.
Share as much information as you can with your cousin and her parents, and ask them to share what they learn from the doctors, or on their own. They'll appreciate your help, especially if you take the time to do some research and reading too.
Good luck.