The sponsor must usually be an adult Australian relative, or that relative's spouse or de facto partner, who is an Australian citizen, Australian permanent resident or eligible New Zealand citizen.
The sponsor must have turned 18 and must be an Australian citizen, Australian permanent resident or eligible New Zealand citizen.
For subclass 116, the sponsor must be the Australian relative who has the medical condition, or that person's spouse or de facto partner.
For subclass 836, the rules are more detailed. If the person needing care is the sponsor, they must be settled and usually resident in Australia. If the sponsor is the spouse or de facto partner of the person needing care, the sponsor must also be settled, usually resident in Australia, and living with the person needing care.
Sponsorship must still be in force when Home Affairs decides the visa application.