He should not leave his wife behind. Application as a Permanent resident means that he'd have to travel home and marry her legally AFTER getting the visa. We both know it may take years for this to happen, and much longer for him to be able to start a visa process for F2A (wife of permanent resident). I went through the IR1 and it took us over 3yrs due to COVID complications, the f2a (Permanent resident applicants) took much longer. I do not understand how marrying her now will make him get denied, unless he wants to stay single and isn't sure about his relationship.