There are many ways to look for help.
The social security disability help is one of the channels and is relatively narrow. It is for long-term disability which means the person has to be totally disabled and cannot work due to the illness for more than one year. Therefore, after one full years, your son may want to consider retain an attorney practicing in the area (they are on contingency payment) to re-apply.
In the meantime, he may qualify for social security supplemental income and he may qualify for Medicaid, etc. to help with his medical expenses.
"Supplemental Security Income (SSI) is a Federal income supplement program funded by general tax revenues (not Social Security taxes): It is designed to help aged, blind, and disabled people, who have little or no income; and. It provides cash to meet basic needs for food, clothing, and shelter."
You may want to start with your county's Medicaid's office, call your county's Department of Family Health Services. Find a social worker to consult. If you recently went to a hospital, hospitals have social workers on site and can help at least direct you to the right places.
Once you and/or he qualify for Medicaid, food stamp, utility, and housing help can come, too. Be patient and continue to look for alternatives.
Below website links can help you start. The medicaid and long-term care services are both governmental websites and programs.
Fiona Chen, MPA, Ph.D., CPA, ABV, CFF, CITP