What you mean her "家属"? Husband? children? parents? brothers/sisters, or other relatives? I think only her husband and children belong to her "家属" . The others are not her " 家属" according to australia law.
It should be OK for her parents and parent in law to get a one year visa, if her "家属" (Husband) has a job and a certain income or enough money in their bank account. but in usual, sisters or other relatives can only get a three months visa.