He himself needs to apply for Welfare at his county Social Services. If he is a Veteran of active duty with honorable d/c there also could be a veteran's benefit, he himself needs to apply at the VA.
Sounds like he initially needs a hospital and some medication for his seizures. Then when his seizures are diagnosed as to cause and possibly under control, a social worker can help him find proper living arrangements. It's nice that you care about his future.