issue legal notice to your mother and sister that after your father death you have 1/3rd share in property . that inspite of being aware that you are 1/3rd owner you are not being permitted to enter the house .

file suit for partition .pending hearing and final disposal of suit you can request the court that you may be permitted to reside in said house .

in case your mother /sister rely upon the alleged will made by your father they will have to apply for probate . both suits will be clubbed together .

amicable settlement with your family members is best option . try to take help of some elders in family .

you have to file a suit for partition of the property that is left over by your deceased father and also seek that the will or gift that is alleged to have been executed by your father does not affect your share. if you do it at the earliest, then there is every chances of your success. more the delay, then you have to suffer the order.

Ultimately you all will have to make a amicable settlement acceptable to you all,so why not to do now.

From what I can infer, your mother and sister attempted to make a fake will of your father during his lifetime, and you had recorded this conversation you had with your deceased father. Whether they (your mother and sister) are now claiming the existence of any such will?

You should follow a pro-active approach and immediately engage a lawyer to ascertain from the competent registrar if any such will has been executed as your rights are subject to the will, if any.

If it emerges that any such fake will has been made then accordingly you will have to set up a legal challenge to the same in the court to protect your legal rights in this property.

Do not issue a legal notice right away. Firstly try to find out if any such will exists. If no such will exists then you may issue a legal notice to them and file a case for division of property in the court. Once the court issues a notice to your mother and sister they will have to appear in the court to obviate the possibility of an adverse outcome.

No court in any part of the world would instantly issue an order which has the effect of ousting or creating proprietary rights. The legal process shall inevitably have to be followed.

well you have to learn to confront your demons . if your mother is autocratic you either be a submissive son obeying all her wishes or step forward to protect your rights . if you get a court order your mother dare not disobey it . she would be hauled for contempt of court if she dares to prevent your or your family members entry in the house . engage a local lawyer . issue legal notice . file suit for partition and injunction restraining your mother from creating any hurdles in your or your family members entry in the house .