Can I claim Head of Household

I claimed my disabled ex-husband as my dependent (we legally divorced). I lived with him and cared for a full year because he cannot live alone due to his health condition. My ex-husband received disability benefits of more than $5,050. My filing status is reported as a single. Can I change my filing status from single to head of household? I read that other relatives can be considered qualifying dependents for the head of household filing status. I finished my return. Should I amend my return?