In Chapter 27/28, Why does Huck refuse to expose the frauds at once? What does Dr. Robinson represent?
Also...Why does Huck say at the end of Chapter 28, “Tom Sawyer couldn’t ‘a’ done it no neater himself Of course he would ‘a’ throwed more style into it, but I can’t do that very handly, not being brung up to it”?
Although Huck knows the men are frauds, & he would love to be free of them and their increasingly outrageous demands, he cannot simply speak up & let everyone know what's going on. There's a chance no one would believe him, thinking he was just a servant who was tired of his position. He may be in physical danger, as the duke & dauphin would probably kill him as soon as they got him by himself. Most importantly, however, is the fact that Jim's safety and freedom is at the mercy of these two crooks. Huck has claimed Jim as his own, but that's not going to stop those two from selling Jim the first chance they get. So, Huck tells Mary first, & devises a plan to get rid of the criminals without putting Jim and himself in too much danger. This does not work out the way he intended, but at least the Wilks family comes out ahead.
Dr. Robinson is a respected member of the town, who was friends with Peter Wilks before he died. He suspects the fraud at once, but when he does speak up with the truth, nobody believes him. Thus, he represents intelligent, rational thought, and how that mode of thinking can be brushed away by powerful emotions. The townspeople are moved by the king's false display of grief, and they are more willing to believe the word of someone they just met, rather than the logic of someone they have known all their lives. This is yet another example of ignorance and sentimentality winning out over logic and reason in the novel.
Finally, Huck mentions Tom Sawyer, because he's proud of the plan he's devised. Tom is usually the inventor of the two, & his extensive literary background allows him to create wild, outlandish stories. This is what Huck means by "style": Tom would have added some exotic elements to the story. Of course, we've learned throughout the story that Huck is a great liar, and his lies work because they come naturally. Attempting a tale like Tom would have failed for Huck, but he is still proud of what he's thought up to catch the two frauds.