Did my father marry a woman and then divorce her after she bore him a daughter? Is my sister’s mother my aunt?

The Shaykh : He says: My father married a woman and divorced her after she bore him a daughter, and she is older than me. Is my sister’s mother my aunt?
Yes, she is not your aunt. She is the aunt of your father’s sister, but she is uncovered to you, even if your father divorced her.
And praise be to Allah, Lord of the worlds. And glory be to You, O our Lord, and praise be to You. I testify that there is no deity but You. I seek Your forgiveness and I repent to You.