Should I reach out and explain why I haven’t answered her messages since I learned what she said to our mother while drunk?

"Should I reach out and begrudgingly TEXT her, explaining why I haven’t answered her messages since I learned what she had said to our mother while drunk again?"

My father died from suicide in 2021. My sister, initially supportive, later drunk-dialed my mother and said a bunch of nasty things about both me and my mother. For some reason, my mother didn’t cut the conversation short and later told me what my sister said,