what measures should we take

My wife's father passed away three years ago. He had a home and a small amount of case from a life insurance policy($25,000). My wife was never sent a copy of the will until about ten phone calls and he then she get after her brother to sent it. It was dated 1986. We know for a fact her father had updated the will since his wife passed in 1998. There is also a house on the lake that her father built in 1970. Until about 1999 the land the house was built on was leased. Her brother and sister bought the leased land about 10 years ago. The question I am asking is who owns the house. It was her fathers from the beginning, just not the land. We think they are trying to make us think they own the house also being they bought the leased land. My wife also according to the 1986 will gets 1/4 of the house but we are thinking the house was deeded to her brother years ago. He never left home and never married. What rights does my wife have? The will states she gets 25 % of everything.