Legal rights of widow senior citizen woman

Dear Experts, My father was suicide in 2003 due to mortgage loan and my mother is house wife (age 68), she has 3 sons and 1 younger daughter (Me). 2nd and 3rd son are married; 1st son and daughter are unmarried. She has lot of loans like jewel loans, mortgage loan and need to give tenants deposit amount (advance). Her sons are not taken care of loans, mother goodness and sister marriage. Her residing house was built by her husband and herself, it is not belongs to their parental money or support. From Past 10 years, she was closed many loans with the help of her daughter salary and her 1st son. She got the house documents from mortgage loan; and having legal heir certificate for her and family members (Mother, 3 sons and daughter). Due to the legal heir certificate her married sons doing harassment's on her and her daughter on property segregation. Now her sons occupied the tenant portion in house and asking their rights in house to use by themselves. In house, totally 2 floors and 5 portions; mother and daughter staying in second floor portion, ground floor 2 portions combined in lease agreement and first floor 1 portion occupied by 3 sons and other portion in 1st floor is in empty, now her 2nd son is demanding to occupy 1st floor empty portion but he is not showing the interest to vacate the lease agreement(3.5 lakhs) tenants . Still she has responsibility to clear the lease agreement and need to do daughter marriage. Hence, we would like to know that who has first rights on house legally - mother or sons and daughter based on legal heir certificate, as well requesting you to provide us the senior citizen Indian rights act details on property. Thanks in advance.