Hi MissiN,
Which nationality is the grandmother?
I am not an immigration expert, but
your
grandmother may qualify for:
1.
A contributory parent visa: if their child is an Australian citizen
2.
Contributory aged parent visa: if the migrating person 65 years or older
3. Tourist visa: if all else fails, she can
apply
for a tourist visa and come for a little while
My understanding of a
carer visa is that it does not include caring for a child. It is more for relatives coming to care for a family member with a long-term or permanent medical condition (of more than 2 years) and will require medicare records or other kind of assessment