Metastatic Mess: Self employed, no super, life or income protection, expired health insurance

I'm pretty sure you will qualify for disability pension unless you have a lot of liquid assets, or partner is still earning a decent living from the business. An old super policy may have life insurance in it, you could start by looking on mygov on the ATO section "find my super". Perhaps if there's an account out there still with insurance you could see a solicitor about getting them to grant the insurance