Earlier your querry was limited to get the remaining 30% of the agreed amount and not to claim any property rights in the capacity of a widow. Now, the complextion of your questions have changed after going through some of the experts' pieces of advice. Now, for me, it appears, if possible, she does not have any reservation to claim property rights and rights in movable property in the capacity of widow. There is no wrong to ask for that. But the necessity is to show patience. If she is asking those rights, it would take time to realize them.
First, the situation changed. There is no validity as far as MCD is concerned. That 70% is her money. The remaining 30% can be drawn if she relinquishes her right in movable and immovable property of her husband. That too if his other legal heirs accept such prposal. If she is interested about seeking her right in her husband's assets, it is better for her not to pursue further MCD or bargaining process with legal heirs/POAs.
In your earlier question in the first part you said that he does not have any property. Later on, about this you are not sure. Now to find out his property, you can adopt three methods:
First method: engage a private detective; he can bring out the banks accounts as well as immovable properties and movable property details in and outside India. Once you get details, you can get certified copies of the same and also get court orders that the amount lying in the bank shall not be disbursed except with the court order. If it is necessary you can get stay orders also for not alienating that property by your inlaws.
She can file a case under Section 19 of Hindu Adoption and Maintenance Act (maintenance to widowed daughter in law) against her father-in-law and mother-in-law and in this move an application seeking the details of movable and immovable properties from them by way of affidavit). Any false affidavit would attract the penal offence and the courts also will not take their affidavits on face value.
This HAMA case takes a prettry long time, say two and half to 3 years. But, in between, she will be provided interim maintenance. The quantum of maintenance available under this Act depends upon the status of her deceased husband, life style and the assets he was holding. If the property, he was holding was self acquired and he drew a will, then she would get the share according to the will only and if her name is excluded in the will, she would not get any thing. If he did not draw a will, then she would be entitled to 1/2 share of his immmovable and movable properties and the remaining half will go to his mother.
She can change her advocate at any time. If she is not in a position to afford an advocate, she can definitely understand to whom she can approach without hesitation.