To me, the answer of Richardus sounds more natural.
The sentence, Is he OK? wouldn't be mentioned so suddenly,
probably people would have talked about him in any ways.
Blah, blah, blah... By the way, is he OK? or How is he?
I would say, 잘 지내죠? 잘 있죠? 괜찮아요? formal / 잘 있지? 잘 지내지? 괜찮아? informal.
Without the subject, because we've been talking about him, we all know who he is.
And, "make it" might mean 하다 (성공하다) in the sentence.
If I were the speaker in the conversation, I would say,
어떻게 하셨어요? or 아니, 그걸 어떻게 하신 거죠? formal/
어떻게 했어? or 아니, 그걸 어떻게 한 거야? informal
In this case, I do put the object in the sentence, but with or without, almost the same, I think.
"아니" dosen't mean not or no in the sentence, actually, it has no specific meaning,
but it's often used at the beginning of sentences to emphasize a little, Oh! or Wow!
Korean stences could be translated in slightly different ways by Korean native speakers,
which would make foreign people confused, but this is the Korean language.
It's important to have your own style as you are learning. Good luck!