My father had a Portuguese citizenship. I am a full-time student in India. Can I and my brother claim or acquire Portuguese citizenship through my father?
You can't "apply" per-se for Portuguese citizenship in this way. You either already have it via your parents/grandparents or not. What you might not have is a passport.
Portugeese nationality law states: (source: https://en.wikipedia.org/wiki/Portuguese_nationality_law)
Portuguese by origin are:
- The children of a Portuguese mother or father born in Portuguese territory
- The children of a Portuguese mother or father born abroad if the Portuguese parent is there serving the Portuguese State;
The children of a Portuguese mother or father born abroad if they have their birth registered at the Portuguese civil registry or if they declare that they want to be Portuguese;
Persons born abroad with, at least, one Portuguese ascendant in the second degree (grandparent) of the direct line who has not lost this citizenship.
Naturalisation as a Portuguese citizen
- As of 29 July 2015, those born outside Portugal who have at least one grandparent of Portuguese nationality, are granted Portuguese citizenship by extension immediately. The new registration procedure replaces the current provision of Article 6, no. 4—according to which a person who was born abroad and is a 2nd generation descendant of a
citizen who has not lost his or her citizenship can acquire
Portuguese citizenship by naturalisation, without a residence
requirement. The amendment still needs to be signed by the President
before entering into law
Therefore, if your parents or Grandparents were Portuguese when you were born then you should have Portuguese citizenship. Therefore, you should just have to apply for a passport and prove your links to your parents/grandparents and prove that they are Portuguese themselves.
I suggest you contact the embassy in India and ask them what documents you will need to prove these links and what else you might have to provide to obtain a passport.