Many visa types (including a range of family, skilled, humanitarian and student visas) allow you to include dependent family members in your application.
When this happens, these family members are considered ‘secondary applicants’ in your application. As such, they must also meet all set requirements applicable to them.
Generally, this includes meeting Australia’s stringent character and health requirements. If a secondary applicant does not meet one of these tests, or is considered ineligible for another reason (for example, if the Department does not believe they are genuinely your relative) their application will fail.