Yes, the sentence "My sister told me about what happened" is grammatically correct. It means that your sister shared information or recounted an event that occurred.
Possible rephrasing includes:
- "My sister informed me about the incident."
- "My sister shared with me what took place."
- "My sister explained to me what happened."
- "My sister told me what occurred."
All of these rephrasings convey a similar meaning, implying that your sister