If my boyfriend is in immigration jail, he entered the US at the age of two is it possible that I could marry him now? And start fixing his papers?

Anything is possible, but more information is needed. How old are you? Are you a U.S. citizen? Why is he being detained I'm assuming without bond? Does he have any criminal history? There are many factors that need to be considered. I suggest that you contact an experienced immigration attorney for a face-to-face consultation and give him/her all of the facts surrounding your situation. (S)he would then be in a better position to analyze your case an) advise you of your options.