Right of children on parent's property.

My parents have made individual wills though unregistered. There is a mention of the two brothers that is me and my younger brother, but nowhere in the will it says anything about inheritance. Both the wills state that in case of demise of one partner the entire property gets transferred to the other life partner. Brother wants a larger share in the property. It is a possibility that he and my mother might join hands and refuse to give me my share after my fathers death. My questions are as follows 1. What happens in case of death of my father? Do I have a legal right over all their properties? 2. Apart from immovable property do I have a right over their mutual funds/shares? And how do I stop them (younger brother & mother) from selling it without my knowledge. 3. How do we settle those properties which are in joint name of both my parents? 4. How do I ensure that no property / stocks are not sold without my NOC by mother & brother