Sister and the husband of my friend are asking for property from his father and mother. There is property in the control of father and mother which has been owned in the name of another person (but definitely not the sister) and sister is threatning to go to court regarding this matter. As both parents are alive and there is no property in the name of sister, does the sister mandatorily deserve share from the property if the father and mother chose to not include her? Does she have a legal share in this matter? And is her son entitled to property of his maternal grandfather?
Note - As they are muslims, can they pursue rulings of AIMPLB?