How to say how are you in Hindi
There is one thing that trips people up here, and it is not the words. It is the ending. Hindi adjectives agree with the person you are talking about, so asking his dad and asking his mum are two different sentences. Get that one vowel right and you sound like you studied.
The polite version, to one person
आप is the respectful you. Use it with parents, aunts, uncles, anyone older, and anyone you just met. It always takes the plural verb हैं, even for one person. That is the politeness, built into the grammar.
The casual version
क्या हाल है is the useful one to memorise. No gender ending, no politeness decision, and it works with cousins, friends, and your partner. If you only take one line from this page, take that one.
Answering
ठीक (theek) does not change for gender, which is a relief. Hand the question straight back with और आप and you have a real exchange rather than a quiz answer.
The Gujarati version, for his family
Gujarati does not split કેમ by gender the way Hindi splits कैसे and कैसी, so this one is simpler. છો is the polite you form, છું is I.
One thing people get wrong
Saying आप कैसे हैं to an aunty. The कैसे ending is masculine, so it lands slightly off, the way "how is he" would if you said it to her face. Say कैसी to a woman. That is the whole rule.