Unmarried Daughter's Property Rights

I am an unemployed unmarried Hindu girl, aged 40 yrs. My grandfather had opened a business and after he expired, my father and now my brother along with my father are handling the business. From few years, my brother has been claiming that my father has grown the business and my brother has earned everything. So, the entire property, the busines and the house which my father has constructed (legally a joint property of my father and my mother) is his. My father is also completely under his influence and for some years they both have been regularly insulting and abusing me and even threatening to throw me on road, and have even stopped most of my expenses, even my pocket money. I am presently living in the house, and being provided food and basic amenities. I have read that all grandchildren have equal right in grandfather's property. I have an unregistered handwritten will of my grandfather on a piece of paper duly signed by my grandfather and 2 witnesses, none of whom is alive now. Can I stake claim on property? Will the entire property, as of today, will be counted as ancestral property, as that business has been the only source of earning of my father and brother. Can that will be a document enough to prove that my grandfather had started the business, which my brother is trying to refute. What is my legal right on my grandfather's business and my father's property, if he refuses to give me anything? What should I do now?