When you find yourself trying to remember a show (or any works) that's on the tip of your tongue but just out of reach, come here - the collective brain of the TVTropes community can probably help. Post all the details you can remember (examples help). If you're looking for a trope, head over to Trope Finder. Have general questions about tropes? Visit Ask The Tropers!
I don't know it, but now I'm curious, since that sounds interesting. It sounds like the kind of book Roald Dahl would write.
Insert witty and clever quip here. My page, as the database hates my handle.This really rang a bell to me, and after a bit of googling, I'm pretty sure that it's Chancy and the Grand Rascal by Sid Fleischmann. The con man is the main character's uncle, not his father, but everything else seems to line up.
First they ignore you. Then they laugh at you. Then they fight you. Then you win.

This was a book that I read several times as a child back in the mid 80s. The viewpoint character was a teenager who somehow wound up traveling with a very charismatic conman who turned out to be his father. One of the concepts was that the conman only really conned people who wanted to be fooled, and generally focused on the greedy. Said conman was extremely tall and had an unusual beard/moustache I believe.
Schemes I remember vividly in the book: