Um.....not to be alarmist, but your sister and future brother in law REALLY need to get this sorted, and the quicker the better.
INS is freaking nightmare. My wife and I spent 7
years ***** around with INS after we got married (she's from India). She was able to work during that time, so it wasn't the end of the world, but it was this constant drama hanging over our heads everytime INS screwed up.
Perhaps they will have no problem at all. I hope thats the case and I wish them well.
Some advice:
1) TRUST NOTHING AN INS OFFICER SAYS TO YOU.
I cannot stress this enough. If you go to an INS office, you wait in an official line, in an offical looking building, and you talk to official looking people with official looking badges. The problem is that these people have next to nothing to do with your case, and they don't have the faintest idea about your case. So when you ask them questions, they are simply going to hand you whatever paperwork 'seems right' to get you out of their face. So what happens if what they told you was wrong, and the paperwork you file gets you deported?
Tough luck. You lose. They are accountable to no one.
2) If anything goes wrong, lawyer up on the spot. Don't screw around thinking you are going to handle it yourself, or go down to some office and 'straighten this out'. Forget it. Spare yourself the anger and wasted time. You will probably only make it worse. Lawyer up on the spot, pay the bills (which really are not that bad), and live your life.
We used Martina Keller in Chicago, and we were very, very happy with her work.
http://www.klc-ltd.com/index.html
3) Don't assume making thing happen fast is better. When we first were dealing with INS, we were stunned by the delays, and we would contantly call them looking for advice. Don't. Our lawyer set us straight on this. The less you hear from INS, the better. Let your case sit idle on someones desk. As long as you have your green card, who cares? When dealing with INS, time is on your side, not theirs.
I really hope that in the end it all goes smooth as glass for them, and that my post is just alarmist BS. But our experience was pretty bad.......