Background - Issue

When Selecting "Parent Contact for Lead" field, few fields are getting populated automatically like "Business Phone", "Email", "Mobile", etc.

1. When removing the Parent Contact for Lead these fields are not getting cleared
2. If selecting some new value in "Parent Contact for Lead", these corresponding mentioned fields are not getting updated with new values

Idea

Resolve these issues which will make lead fields latest based on the "Parent Contact for Lead" value.