Daughter and daughter siblings share in immovable property of father

Hi,
Below is a scenario;

Scenario: there is immovable property on the name of person a. Person a has died 45 years ago. Person a's wife has also died. The property is still in the name of person a but is in possession of person a's sons.

Now i want to clarify two things;

1) if daughter d of person a files a suit in court for her share, what would be the possible outcome of this case?

2) if daughter d has died and her son, files a suit in a court for his mother's share (daughter d's share). What would be the possible outcome of this case? Is the daughter's d son eligible to claim her share?

Kindly provide your valuable legal advice.

Thanks & regards.