While everyone understands there is an added level of uncertainty when taking a start up position, your situation sounds more unusual than most considering that it does little more than screws up your career and short term family plans. You can't really say you worked at this company, you've already gone through what sounds like a lengthy job search and turned down all positions that came up besides this one, made plans with your family to move to the States, and then a week after getting 'hired' you had to make other plans.

I'm not sure why you say you like the founders when they treat people like this. This is a serious blow to your life that they are responsible for.