A visa for my father in law.

My father in law wants to come and stay with us until I finish university which will be a few years yet. He gets $20,400 a year for his retirement and he'd be able to live with us rent free as we have a 4 bedroom house. Is it possible to get him some kind of visa? Even if it's just a long term visitor visa?

I don;t think it will be possible unless he intends working and qualifies for an employment category.  He doesn't have a large enough income to be a retired person of independent means.  The best he can do is to come as a visitor for 6 months in the year.  He could apply for an extended multiple entry visit visa to do this.

Vicky