It will never come to pass. It should also be remembered that India was created by the British, whereas prior to occupation it was numerous states each ruled by a Raj.
India has a very peaceful image in the West, largely due to Mahatma Gandhi's approach of non-violent action. However, the truth is very different. There is an extremist Hindi right within India, and life outside the major cities is very different to life in Mumbai etc. 1000s of Indian Christians have been raped and/or murdered by Hindi fundamentalists, and the government has embraced the American/British anti-Islam approach to politics.
Pakistan and Bangladesh are both Islamic states, and are about as likely to join with India under a Hindi government as America is likely to become a Shinto state, praying and idolising the Japanese Emperor. Why should they give up the independence that they fought hard for?
Does your friend say that she would be happy to have a re-unified India with Islam as its ruling religion? I bet she hopes for a unified Hindi India. Ask her.