This is a very big responsibility. Along with the disabled paycheck, assuming you get one. (If not, then you should.) You can get help from the state. They will help with medical care, food, transportation if they need it. You may even be able to get a nurse to help here and there. Also, the state will license you to take care of your twin. aka pay for doing it. To inquire about all this, call your local DHS office. Just do a search in Google for "city your in" Indiana DHS office.... Make an appointment with a Social Worker and they will get the ball rolling for you. Depending on how quick you need the services they will help you get it quick. Good luck and God will repay you for your kindness.
As for college, I suggest transferring to an online school. They are great. I am going to University of Phoenix. Do NOT use AIU!!! (Bad experiences) You are capable of anything you put your mind to.