getting marry for the second time and he is threatning us dat he will not give any share in property

hello, i will explain u in detail regarding our properties and our family problems hoping for a solution.we belong to a muslim family and my father is planning to get marries the second time.he is already married with my mom for 27 yrs.they are 3 kids(me(26).my sister(24)and my brother(16)).due to alot of tensions between my parents,my father has decided to get married the second time.he has told us that he will not bare any of our financial responsibilities nor he will give us anything from his property. The properties which my father own: 1.a shop - (which is an ancestrial property aftr my grandpa death it got transferd to my fathers name). 2.flat no (1) -(this flat is registerd on both my parents name.) 3.flat no (2) - (this is registerd in my fathers name but he has to do complete payement of it) So,the problem is that my father is preasurising my mother to give an NOC of that joint flat.he has already threatnd us dat he will not bear any of our expenses, will u please tell us dat what should we do now.is der any contract or something which we can make be fore giving that noc that whatever property my dad owns he before selling it he has give us our shares or should take a consent.or anything legal way which we can take. (we are tensed that if my father gets married the second time he might transfer all his property to his second wife). Please help us with your valuable advice. Thankyou.