Two things, first most important, FEW players in europe make that kind of dough and the ones who do often have NBA experience and are paid for their celebrity. I don't know who started the myth that D1 basketball players who aren't draft worthy go over seas and make 6 figures typically but that's a load. Two, his game is not that good, he is undersized in contrast with other 2guards. Even over there and when it comes to undersized players, you need to be exceptional at something. Either athletically or as a shooter. He isn't at either. He's not Melvin Levett and he's not some unconscious 3 ball kid.
His ceiling is high, but he's too unpolished at this point. It is a bad idea with his potential to leave just now. He'll likely end up making 20-40K a year and given the caps those teams put on the number of foreigners allowed, he may not be able to get on a team. Consider the number of kids who won't be drafted at the end of this season that will be going across the pond and are considerably better. It just seems very unrealistic to think he'd make much out of it.
I'm not saying he won't, just that it's a bad decision if he does.