1. As rightly explained above, insurance compensation received on account of the death of an individual will not be subject to tax in the hands of the recipient by virtue of sec 10(10D) of the act.
2. However, this amount will not be subject to tax in your hands. But if you want to transfer this amount to your mother in law's account, then gift deed can be executed and by that way income arising out of Rs. 50 lakhs deposit will be taxable in her hands.
3. Mother in law will be considered as relative for the purpose of sec 56(2)(x), and any gift in the form of cash or immovable property provided to her will not be subject to tax.
4. That way, if your mother in law is a senior citizen then more benefits are available from the Income-tax point of view. Execute a gift deed for the transfer of Rs. 50 lakhs.
Please correct me if the above solution has an alternative view.