Whom to approach for "maintenance and welfare of parents"

Advise her to contact Legal Services Authority, and they will be in a position to guide her properly, including asking her to make a request through LSA in writing to son till filing of complaint to Police for neglecting her.   They will be in a position to guide her without charging single paisa. and they are experienced in the same issues.

Senior Citizens Act, 2007 is not a good Act.  It is not beneficial to her.  Go to nearest metropolitan court and engage an advocate from legal aid and file Section 125 cr.p.c. maintenance case and she will get very handsome monthly amount.  Within six months from the date of filing the petition, she starts to get interim maintenance.

As well advised by expert lawyers have, more  particularly learned  advocate Mr.Chandrasekar, she can find relief by filing maintenance case under section 125 cr.p.c. and also an interim maintenance application on the same lines under the same provisions of law as an interim relief.  You may approach the District legal services authority from where you will get free legal assistance through their panel advocates. 

Human angle is also involved.  No mother can file suit against son, though he is not looking after her.  All the efforts taken must be reflected to the concerned Court.  Once LSA takes up, it first summons her son and take his counter/written statement for PLC.

This also strengthens her civil case for maintenance.

Simply you draft an application on behalf of your Grand mother stating her facts more particularly monitory sufferings and its need for maintenance and medical expenses, get it signed by your grandmother or put her left thumb impression on it and after affixing appropriate Court Fee stamp  submit the same before the District Judicial Magistrate for relief and redress. For such purpose you can take help of the Bench Clerk of the District Judicial Magistrate. 

this is fit case for apporch before Ld ACJM of CJM having jurisdiction for her maintenance and file petition under DV act of 125 CrPC . But i Prefer to file petition Under DV act . If she has no financial ability she may contruct to DLS ( District Legal Service Authority)

As to the given facts it will be more efficacious and effective to submit a simple complaint against her son without following any provision of law to enable the Magistrate to treat the same as a complaint under a particular provision of law as to his choice which will be more effective and forceful.