Yes she will.have share in the property the 50 percent share of your mother in law shall go to her daughter.
See you have confused the facts a bit or I may say complicated it , so as I can understand is .
There is father F. Who is having son F and daughter M(your mother in law). No F gives property to his wife W. Who expired in 2005. On her demise the property will equally divide between S and M as no will.from W.
Now S expired in 2018 and M in 2010.
So M share goes to her on ly daughter your wife and S share to his daughter and wife.
So your wife is 50 percent owner of property and she can file.a suit for partition and possession if the S family is not ready to give her share and register partition deed mutually.