Leaving All The Children Behind

So I have a 7th grade class of students in which nine of them read at or below a 3rd grade level. Two of them read on a first grade level. Five of them were previously in a self-contained classroom, but put into the regular education classroom because “they can do the work.”
The special education teacher told me she doesn’t understand how one of these kids could be passing my class because he reads on a first grade level. I told her I have to grade him differently than everyone else because he obviously is not able to do all of the work. She said, “Just fail him and they will send him back.”
Which brings me to Victor. He reads on a 2nd grade level (well, we think. He refused to finish the test, so they just graded the few questions he answered.) He will do a good 10 minutes of work for me and then he’s done for the rest of the day (80 more minutes). He is very pleasant for me, but it is pretty much impossible to get him to do any more work. Even if I sit beside him and try to work him through it. Well, I went to the special education team to tell them that he is not doing well at all in the regular education setting and needs to be back in a classroom which can better accommodate him. I was told that he has, on multiple occasions, threatened to kill his special education teacher. Therefore, “he doesn’t threaten to kill you, so we’re going to keep him in your class.” So, this one, even if he fails every assignment, is with me for the long haul.
Another child in the same class, Dennis, is also on a 3rd grade reading level. He disappeared a few weeks ago because he got suspended. The suspension was for three days, but he’s been gone for a good two weeks. I found out today he has been placed in high school. In the middle of the year. From seventh grade. To high school. He can barely read.