Property Through inheritance

My sister recently lost her husband. There is no will. Now two properties are left behind her Husbund. 1)One is in name of her mother inlaw and her husband after her father inlaw's death through heritance. 2) And another is in name of her husband since purchase of the property. She has five years old son and has no sources of income. Her mother inlaw is foreign citizen. Now can she include her name in these properties? And if she can such then how much share she can take with her son? Plz, help me in getting her right in both the case.