Who is the owner of the property ? If the owner was your dad then your mother only has 1/3rd share in that property with 2/3rd divides equally amongst you to brothers.

need details as who is owner and how he got this property . is there any will?

after your father s demise, you, your brother and your mother and your grand parents have an equal right in the property. you may not be able to transfer 80% share in the property.

i agree with Adv Gupta