There is no way that this dealer was intentionally trying to cheat you. A cheater will not keep trying to cheat after he's been caught ONCE, let alone twice. No; what you've encountered is a dealer who's prone to mistakes, not all that rare in the industry.
You've actually stumbled upon a rather lucrative situation for low-stakes play. If you play at this dealer's table LONG enough, you'll find that in the long run the mistakes will be in YOUR favor just as often as they won't. When in your favor; you keep your mouth shut. When against you; just politely correct the dealer and laugh it off.
As a matter of fact; I've found that playing a tip for this dealer once in a while oftentimes triggers a subconscious desire in him to WANT you to win, which sometimes will result in an increased frequency of mistakes in your favor.