I know a homeless man who needs assisted living accommodations but does not have insurance. What can he do?

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.

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.