GPA executed from abroad does not require registration in India and it cannot be registered  in the absence of person giving GPA. The GPA from abroad has to attested in Indian Consulate in foreign country. The procedure is, draft a special power of attorney on Indian stamp paper of 100 rupees which  is available in all countries  or even on white paper giving SPA to any of your relatives/friend to sell the property.  Go to Indian consulate/high commissioner and get SPA attested which  the consulate official will readily do. Send the SPA to the person named, he will take the SPA to the District Registrar who will validate it by putting his seal and signature. Fee for validation of SPA is 1 % if it is given to blood relation if given to other person it is 2% of government valuation of the property. With the validated SPA you property can be sold by person named and proceeds can be deposited in your account.

Dear Client,

Yes, GPA can be registered anywhere in India. Registration of GPA in India is done at the offices of the Sub-Registrar. GPA in India has to be prepared on stamp paper of appropriate value. The Principal and the GPA Holder have to visit the sub-registrar office with the GPA for registration.

1. Draft the Power of Attorney deed online or hire a lawyer in India to draft it for you.
2. Get the deed attested by the Indian embassy or consulate in that country. Any Notary from there can also attest it.
3. The person making the deed, the Grantor, should sign the deed in all pages.
4. This attested deed should be sent to a known person in Indian address by registered post or courier.
5. Finally the person to whom the deed is sent should get it registered from the local Sub-Registrar office or Sub-Divisional Magistrate office in India, by paying the appropriate registration charges applicable in that State.

If GPA is attested before Indian consulate then it is not necessary to register the GPA on india 

The GPA executed by the Executant/Principal  in a foreign country country needs to be adjudicated before the Sub registrar within the residential jurisdiction of the power agent. 

So he can get it adjudicated before the concerned authorities where his residential address is located. 

I believe you already got it attested by the Indian embassy or consulate or Any Notary in that country..

Your brother can get it registered from the local Sub-Registrar office or Sub-Divisional Magistrate office.

It has to be registered at bangalore preferably where the property is situated

First you need to get the PoA suitably drafted by a competent lawyer to serve your purpose. It has to be executed in the USA and either notarized or attested by the Indian Embassy/Consulate there. Then, it has to be adjudicated by the land registry having jurisdiction over the property within 3 months of its arrival in India. Once this procedure is over, your brother may act on your behalf as your power agent legally.

- Since, you are residing in US , then you can authorize your brother for the said work after executing GPA/POA 

- The said GPA/POA should be notarized as per rule of US , and attested from the Consulate of India , and further registration of that POA is not mandatory.