What kind of documentation would be best suited for this?

I am an NRI, currently staying in USA. I have a house in India. I am not interested in either renting or leasing that house, but prefer to use it as vacation house while I visit India with my family. Earlier, I had allowed my younger brother and his family to stay with us in the same house. Things didn’t work out well. He started demanding me to transfer to my house to his name. When I made it clear that he can just continue to stay at my home for free and nothing more, he become aggressive, trashed my house, deserted and just walked away. We did keep the house locked for few months, but neighbors were kind enough to quickly convert my house into a garbage disposal center/dumpster. Now, I want to allow my in-laws (MIL, BIL, SIL and her family) to use my house as their secondary home, so that they can access my house in my absence, stay for few days if they want to, as well, will take care of necessary repair work and maintain our house in our absence. My in-laws are well-to-do, have their own house, they are rather doing a favor to me by agreeing my request, will visit my house whenever possible. But my brother and his family may create issues by visiting my house and may start unnecessary fight/argument with my in-laws. I want to ensure that my in-laws are well-equipped with proper documentation from my side so that if things turn ugly, they may call local-police and apprise them they are staying in my house at my instruction, and may request local police to send back my brother/his family peacefully from that place. What kind of documentation would be best suited for this? A special power of attorney from my side to my MIL, BIL, SIL and her family? Local Police will need to recognize that my in-laws haven’t force entered into my house, but rather acting as per my instructions. Any sample format? Also, I want to mark this document as valid only for 11 months ( less than a year).