Yes! This could be a workers comp claim and he would get 100% of medical coverage. Contact an experienced South Carolina workers comp attorney. The consultation is usually free, at least with me it is.
You would apply for Social Security Disability based upon the accident and being unable to work 18 months. Medicare comes with that. Medicaid is based on income and I think you can apply any time. Here are some SSDI FAQ and answers http://www.ryanmontgomerylaw.com/Social-Security-Disability/Social-Security-Disability-FAQ.shtml
Well you were not at fault so in theory you do. I see you are in Greenville which can be very conservative in verdicts and payouts on soft tissue cases. You should be able to get you medical bills covered and then maybe a little in your pocket. An experienced injury attorney can help reduce the medical bills as well so you put more in your pocket.
Probably throw the book at you. You weren't shook up- you didn't want to get in trouble. Now, they could charge you with fleeing the scene, driving on a suspended license (is it the first time?) the may try and say you contributed to the accident, etc. So instead of paying a fine for not having a license you will still get that plus other charges now.