Well, the hiring minimums for Southwest are 1500 hours of turbine time (or 2500 total time), AND 1000hours of turbine PIC. Additionally, JAA type ratings don't transfer over to FAA licenses (generally speaking) so you would still have to do part of the 737 type rating course again (at least it is much cheaper in the States than in Europe). Anyhow, this is the easy part.
The hard part is the greencard. There is a greencard lottery every year. Depending on which country you are from, you may or may not qualify for the green card lottery. Having a half brother American doesn't up your chances of getting a greencard or work permit as far as I know. In fact, one of my best friends is a foreigner and when his visa was about to expire, he explored options to stay in the US. He has relatives living in the US and the immigration lawyer said that it would make it actually harder for him to get a visa extension.
The alternative is to get married to an American, which depending on your situation, might be easier or harder than the lottery
