1)once gift deed is executed duly stamped and registered you are absolute owner of property

2) if you are not taking care of your father he can make application before senior citizen tribunal to set aside gift deed 

regularly transfer funds to your father bank account to prove that you are taking care of father financially 

1.It appears your father has gifted his share by a registered deed of conveyance then he can not take back his share and revoke the deed already done.

2. So even if his second wife is putting pressure the same is not likely to give much result and the share already transferred to you can not refunded to him anymore.

3. So take care of your father ad if possible keep documentary proof of the expenses you incurred on upkeep of your father. 

4. If you father is in control of his second wife then he may file case before the Senior Citizens Tribunal which has power to revoke the gift deed if it is proved that you are not taking carfe of your father properly.

You must have got their share through release deed. Don`t worry, release deed cannot be cancel. And under senior citizen act, if any application filed let me know. In that act, only gifted property can be recovered that also on limited ground.

Dear Sir,

Yes, it is a very powerful Act under which Asst. Commissioner (Revenue) has such summery powers. I have draft so many similar  orders. You have to take proper guidance to come out of the trouble. The law is as follows.

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The Maintenance and Welfare of Parents and Senior Citizens Act 2007

What are the important features of the Maintenance and Welfare of Parents and Senior Citizens Act 2007?

Ans. The Maintenance and Welfare of Parents and Senior Citizens Act 2007 envisages providing need based maintenance to the parents/grand parents from their children. Tribunals will be set up for the purpose of settling the maintenance claims of the parents in a time bound manner. Lawyers are barred from participating in the proceedings of the Tribunals at any stage.

The Maintenance and Welfare of Parents and Senior Citizens Act 2007 also contains enabling provisions like protection of life and property of senior citizens, better medical facilities, setting up of old age homes in every district, etc.

Yes it is revocable on basis of any harassment to the parents by children

If your father had transferred his share of property to your name by a registered gift deed then he cannot claim it back for any reason including senior citizen's welfare act.

There are chances that if he had transferred the same by a registered setlement deed.

You can challenge the same in the court of law properly in case he files a case for retrieving the property.

You gather and create proper documentary evidences to prove that you are taking care of your father properly so that in case he is approaching court, you may produce the proofs before court to deny his allegations.

Dear

The settlement deed once executed cannot be revoked easily that too after such a long time. 

Your parents can only file a case for maintenance under maintenance and welfare of parents and senior citizen act 2007.