What country he is from? How, when and on what visa did he come to Spain? Did he apply for any status in Spain or any other EU country?

Yes, it's possible that he will have to go back to his home country. It's also possible that immigration to the USA may take significant effort and time.

His situation is much more complicated than can be discussed on a public forum (him being an illegal immigrant in EU, and planning to move to USA). To receive legal advice regarding your fiance's chances and options, you need to consult a U.S. immigration attorney and provide lots of additional information about your fiance.

I offer confidential telephone or email legal consultations and assist in matters of the U.S. federal immigration law to clients from all 50 States and internationally. If you’d like to schedule a telephone or email legal consultation, need legal advice or help, please let me know and I’d be glad to help you. Please email at Attorney [@] law-visa-usa.com or LubaSmal [@] yahoo.com . Or you can TEXT a request for a consultation with an Attorney to 1-402-238-1238. Office Telephone line is 1-402-210-2040 (please email first to schedule a consultation).

Note: The above response is provided for legal information purposes only and should not be considered a legal advice; it doesn’t create an attorney-client relationship. If you would like to request a follow-up confidential advice on your specific situation and regarding U.S.A. immigration-related issues, we can offer a paid consultation by telephone or email to clients from all States and globally. Please visit our website http://www.law-visa-usa.com/contact_us.html for more details.

Yes, this is a confusing question. We specialize in consular processing--which your fiance will need to do, regardless of hs nationality. That processing will need to occur in his home country, assuming it has a U.S. consular presence. If your fiance is in Spain illegally, this may be an issue for Spain, but not necessarily relevant for a U.S. K visa. Another possibility is that your fiance may be in the U.S. with adjustment of status available. Call us at (805) 549-7745 or see www.harrellimmigrationlaw.com.