Can anyone recommend a liberal arts or history professor at MIT? My son has asked me to help me find a good course that will fit into his schedule. He would take one from Paulette Meier, who was recommended to me by ISI, but for a conflict.

I have not taken any history courses yet, but I do plan to take Maier's course "America History to 1865." From what I have seen, she seems to specialize in American History and teaches classes such as American Classics and American Revolution. Although I may not have taken any history classes, I have taken several Literature classes. I enjoyed Prof. James Buzard's two classes: Foundations of Western Culture and Victorian Literature. His specialty is the latter one, so the former class is taught by a different professor each semester. Another professor that I found engaging was Prof. Lipkowitz; I took her fiction class last year, and now I am taking her course on the Bible, which, in my opinion, is one of the most interesting classes available at the Institute. As for philosophy, I am just getting acquainted with the major, so I do not have the experience from which to draw conclusions about the professors teaching these classes.
Another option available to your son is cross-registering with Harvard, which will open up a sea of possibilities. For one, he could take classes with Harvey Mansfield, or other courses that deal fairly with Western culture. However, I think the deadline for Harvard cross-registration has already passed, so this might not be a useful suggestion.
I hope I have helped in some small way.