No aunt is not a proper noun.
Proper are specific. They are the names of things people etc. so they start with a capital letter.
Many Filipinos vote for Duterte.
But just because it starts with a capital letter it doesn’t mean that it is automatically a proper noun.
The Orwellian culture is quite interesting.
Orwellian here is used as an adjective. We know that because it precedes a noun which is culture.
Proper forms of words start with capital letters. You just have to know whether it is a noun adjective etc.