Question Details:He just wants to come here to get married and he has to go back to UK because he is still working there. We just want to know what visa type he should apply to get marry in US? Also, please let us know if we need to perform any precautionary steps.
He cannot apply for a fiance visa since you are not a US citizen. He may apply for a tourist visa, but it will be difficult, because he must disclose that he is engaged to an LPR. However, that is likely his only option, unless you can qualify for citizenship.
