Contacts with 3 years old Grandson with father and Grandparents.

After settled marriage of my son, we came to realize and feel that my daughter-in-law (whose mother died committing suicide before marriage of my son, fact of which matter father-in-law of my son suppressed and told that his wife expired due to heartattack) is behaving abnormally sometimes after certain interval. This I brought to the notice of her father who always denied about any psychological ailment of his daughter and, whenever his daughter started to behave abnormally at my house, her father used to come to my house and took his daughter on the plea of getting her refreshed for a few days after which she used to become normal for a few months. This matter gradually started to increase day by day and my daughter-in-law never agreed to visit any psychiatrist for checkup on the grounds that she is totally normal and, it is her father’s advice not to meet any psychiatrist as per our request to her. Several times she attempted suicide also. Meantime, my son was blessed with a baby-boy who is being totally neglected by his mother continuously since she expected a baby-girl. Even my grandson is not being timely given his food, medicines etc., but whenever he cries, he is being seriously beaten up by my daughter-in-law without any mercy whatsoever. She is a working lady and, as such, busy in her profession from 8 AM to 8 PM during which period my wife, grandmother of my grandson, takes all cares and looks after the child of 3 years. Recently, my grandson has also been admitted in a school but, meantime, following facts happened in our family: After making hue and cry and serious quarrel with my son unnecessarily, my daughter-in-law went to her parental house and keeping no contacts with us even not sending any photos of our grand-son through Whatsapp and/or allowing my grandson to talk to us over phone with us although before going to her parental house she was advised to send us regular photographs of our grandson through Whatsapp message and get my grandson connected with us over phone for which purpose she was given my separate SIM Card of Mobile. At the same time, she is also not sending my grand-son to his new school where we can see our beloved grandson at least once in a day. Meantime, recently she lodged Case under Section 498-A against all of us and, for which we are taking the advice of our local Advocate to overcome the situation immediately. At this juncture, how can we get our beloved grandson under our custody and/or regular contacts because, we are sure the baby is now seriously neglected for the reasons her mother is staying away from home from 8 AM to 8 PM and, his paternal mother is stepmother of my daughter-in-law and his paternal aunty (sister-in-law of my daughter-in-law) is having her own 2 school going children. We are also seriously worried about health condition of our grandson. We have no information about him. In a nutshell, my daughter-in-law and all members of her paternal house have severely and jointly cut off all contacts of my grandson with my son and our family members. Kindly advise me the best legal way of getting immediate direct contacts of my grandson with my son and all members of our family. We are seriously not only worried but also under mental agony. Please advise per return mail.