Currently the SSA determines which benefit a recipient receives based on his/her PIA. If a person has not worked long enough to earn the required credits should one become disabled, they will not qualify for SSA benefits, but instead SSI benefits.
The Supplemental Security Income (SSI) program pays benefits to disabled adults and children who have limited income and resources. People who have worked long enough may also be able to receive Social Security disability or retirement benefits as well as SSI. Children of disable parents that fall into the latter program often times will not qualify for the benefit of the disabled parent, leaving the able-body parent the sole provider.