As none of the insurance companies offer cover for persons aged over 70 years, and as existing diseases are not covered in any case, the health insurance route is not useful to take care of your parents.
My suggestion is that Banks or Financial Institutions provide long term loans to tax payers on liberal terms to be repaid in small monthly installments. The loan amount may be used to purchase single premium unit linked insurance policies with the rider that withdrawals from the policy can be made only to meet the medical expenses of dependent parents.
For senior citizens who have nobody to take care of them, the minimum the Govt should do is to refund taxes paid by them in the past to meet medical expenses.
