Visas for wives and children of partners offered a job in the USA?

My fiancee has been offered a job in dallas, he has claim to citizenship as a child of an american citizen and is currently going through the process of getting an american passport. Now I'm aware of the cr1 visa and the k1 visa for wives or fiancee and also the k2 for children however, I know this takes upto a year to process and recieve sometimes. How are people managing to move with their partners and kids so quickly or am I missing something? Any advice much appreciated