Property share

My father has total 7 children ( 3 sons and 4 daughters). My father, one of my brother and myself(elder son) bought a house paying money in 3 shares. And we stay in the house for 25 yrs and always paid one-third share in house renovation, Sister marriages etc(divided among 3 brothers). But now the house is not in good condition and we want our share in it. My father shown me the registration copy stating one fourth of share in house(i.e divided among mother, father, one brother and me). At the time of buy I was bit small to look into house registration matters. They want me to take money at low market rates for my one-fourth share of house so that they will start new construction, Otherwise they will leave one fourth area(giving 1/4th of house front) and construct their house at rest 3/4th area. Legally can we claim it to be divided among 3 shares (Father, one brother and myself) or can we claim in 2/4th of share (divided among my mother and father). What can we do if they start destroying the old house and start construction over the area without our consent. What can be the possible outcomes and how long will it take to settle in court. Thanks in Advance!!