This is an upper level class, and the student is a junior, I believe. The counseling center clearly knew him well. They told me that I cannot get security to escort him out unless I ask him point blank "Are you going to harm yourself or someone else?" and he answers yes. I already used the strategy of sending him to the counseling center, but it didn't help.
This makes me feel even more sure that the counseling center can't figure out what to do with the kid and are foisting him off onto anybody else. Tell me, are you new in your department? Is it possible that the other members of your department also know about this kid, and the reason he's taking (if I didn't misread your original post) four classes from you is that they all know him, want no part of him, and are sticking you with him?
Or did you mean "the second day that this class met," etc.? I am not sure what you meant by "the fourth class." In any case, do the best you can, which could be better if you had a competent crew at the disabilities office. Best wishes, and do see what the Dean of Students can do for you.