Hello all,I would like some immigration advice from the community. I came to the US in 2012 on a K-1 visa. In 2017 I became a U.S. citizen and have been living in the USA with my husband, who is a native U.S. citizen (we have been married for 14 years). Now we are thinking of bringing my adult son, along with his two children (ages 17 and 14, Polish citizens), to live with us. How much money do we need to sponsor them? What category would they fall under, and how long would they have to wait? In my K-1 application, I mentioned his name just in case he would try to join us. Is it possible to get them green cards and have them live legally in the U.S.?