Update parent record activity when task fields are updated

[samadam]

How can I update parent record activity when related task fields change? I have the updates captured in Activity on the task record. I want to update the parent with these updates as well. I am trying to do this using BR but not sure how to update the audit log on the parent. Any ideas?

[samadam]

I am trying to do this using business rule on update but not sure how to capture it like it populates in task activity log. like the field name new value etc unless explicitly done. Any chance we can capture the activity log to the parent as well