Prelim; I'm not a soft touch when it comes to death so I assure there's NO harshness intended in my chosen words.
Ando apologies for the wall of text.
How do you know seeing a sad face won't benefit her? That's for her to be the judge of.
Let me tell you people handle it differently both the dying person and their friends and family, which is fine.
On top of that not every context of dying is the same either.
Is there a correct way approach it?
No I don't think so, but youre now more than likely going to come across self interested folks who might just tell you that showing compassion is what you 'have' to do (which kinda defeats the point if it's contrived)
To answer your question, how do I approach it. Nothing profound, but genuine. My mother only has days left to live, from 3 years of sickness as a consequence of a addiction and bad life choices.
Am I sad she is dying? No.
Will I miss her, No.
Is there a meaninginful significance in my breaking our silence to let her have the experience of death that she wishes to have?
I didn't think so at first, but hey, theres a meaning which has appropriated itself.
Why is that? well because it was Her death. Not mine. I can cross my feelings and inhibitions for this once, will it change the past, no. But that's not the point. I get to pass my longtime limits and she gets to have a passing she desires.
But that's only my agenda, hey it was asked for.
Your Aunt is the one that's dying. This wont change, nor can you control it, but you can control giving her a meaningful goodbye if you choose.
Seeing her sick, yes it's sad naturally enough and you have the right to be sad, but it won't kill you. You will be fine eventually, you get to live.
You just need to sit down with yourself and ask a few more questions.
Are you close with her?
Would you like to or care to see her if you were in her position?
Also remember it's your Mother/father who is also losing a sister.
You don't have to appease people and visit her if you feel guilty or coerced, but remembering how they too will react differently.