Legal guardianship status

Dear Members, How to confer legal guardianship status of a minor girl to her maternal grandmother by her mother while her father is still alive,stays separately from them ,doesn't provide any financial support to them? The girls mother is economically sound,has job and they stay with maternal grandparents.Now,the girls mother wants to ensure that no property/money to go to the husband in the event of her sudden death,if happens so and the girl should inherit her 100%propery and her maternal grandmother should be her legal guardian and the girl stays with her maternal grandmother. How to manage,please advise.