I'm seeking your kind advice on my issue below:
My grandfather registered a property release deed in 1975 which was signed by his four brothers as well, in front of the registrar and attorney. The property title wasn't changed immediately and the property bills keep coming in the name of his father ( my great grandfather) even today. None of his brothers are occupying the property since 1975 and they haven't contributed to any maintenance with the understanding that the separation is complete.
Now we have to repair the property since it's in shambles and we need to change the title to my parents, so we submitted an application. As per process all my grandfathers brothers were sent notices and their children appeared in court. They're now saying that they didn't sign the deed 38 yrs ago and that's its invalid. My grandfather passed away in 1992 and two of the other siblings also passed away.
Can the opponents prevent us from changing the title to my parents names in spite of a registered deed ? If yes, what options do we have ? What should we do ?