How to draft family-based general power of attorney?

I want to draft a comprehensive Power of Attorney (POA) covering all my assets—movable, immovable, bank accounts, PPF, mutual funds, demat accounts, lockers, etc. The POA should be structured like this: First, my father will hold the POA. If he is no more or becomes incapable, it passes to my mother. If she is no more or incapable, it goes to my brother. The POA will be registered in Maharashtra, India. I am willing to pay ₹1000 for a professionally drafted document.