It could be several things. You need to have Aunt checked out to determine root cause before doing anything else. Keep in mind that she is an adult even if she doesn’t hear so well and she should retain control over her own well being. Come to her from a place of love and understanding

Boy do I understand this one! My husband and I have gone a few rounds on this subject 🙄 to the point of setting up a hearing test....which I passed with flying colors! HAH 😏
After a long while and my Parkinson's diagnosis was confirmed I looked it up and spoke with a friend who's husband is recovering from a brain aneurysm. It is not the volume! It is the brain needing to comprehend. Try to say it again a bit slower and more explaining like you would to someone who might not be fluent in English. The words come in but can rattle around inside the brain till it registers.
I hate it 😒

I tell them in a softer voice to get hearing aids and then show them mine!

aren't we all....

Sometimes I do