What does the doctor think of Jim?

Many people wanted to punish Jim for running away and causing so much trouble. The Doctor comes to Jim's defence. Despite the offensive language, this is actually a white person complimenting Jim,

"I never see a nigger that was a better nuss or faithfuller, and yet he was risking his freedom to do it, and was all tired out, too, and I see plain enough he’d been worked main hard lately. I liked the nigger for that; I tell you, gentlemen, a nigger like that is worth a thousand dollars—and kind treatment, too."