As JandE has said it is extremely difficult to obtain a carers visa. You have to be assesed as to the level of care you require and as JandE has said you must be able to prove that there is no one here that could provide assistance.I discussed a visa application once, with Immigration, for someone to assist in a similar capacity.
The reply that I was given was if there was no one in Australia that I could employ for that same position, then I could apply and there may be a chance of approval.
However, if there were people that could do that job, then I had zero chance.
I stated that I was not employing or paying that person, a relative, but they said that bit is not material to them.
I gave up on that idea at that point.
