Non-accompanying members of the family unit
 

Could anyone help me with this urgent question plz, many thanks in advance!!!

Both my parents are now in Australia, but my father's visa is expiring this coming Friday. Since we can not extend a visitor visa, we need to apply a new visitor visa for my father.

In the application, there are 2 questions really confused me a lot, they are:

1. Are there any other persons travelling with the applicant to Australia?

2. Does the applicant have any members of their family unit not travelling to Australia who are not Australian citizens or Australian permanent residents?

Since my mother is in Australia, should my father list her as the family member who is travelling with him OR to define her as the family member who is NOT travelling to Australia?

Any suggestions will be appreciated.