Yes, your petition will be invalidated if he marries while you are still a lawful permanent resident.

If you’d like to schedule a telephone or email legal consultation, or need advice or help, please let me know, and I’d be glad to help you: Attorney [@] law-visa-usa.com or LubaSmal [@] yahoo.com .

Note: The above response is provided for legal information purposes only and should not be considered as legal advice. This response doesn’t create an attorney-client relationship, which can only be established through payment of a fee. If you 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. Our contact email address is Attorney [@] law-visa-USA.com

If your son marries now, he won't have a preference category any longer. That is, right now he is the unmarried child of a permanent resident (Family 2A under the Visa Bulletin). Each month the US Department of State releases a Visa Bulletin. So, if your son marries there is no visa category for him.

If you obtain U.S. citizenship, there is a category for married sons of U.S. citizens. But this is Family 3rd Preference -- and a much longer waiting time. However Becoming a U.S. citizen will cause your son to wait longer, but if you become one and he is compelled to marry then this would be the only alternative. But, you must be sworn in as a citizen first.

If your son is not going to marry, and he can wait, then you should probably consider waiting to obtain U.S. citizenship because the waiting times are longer for unmarried sons of U.S. citizens than they are for children of permanent residents.

Note, most out-of-state attorneys can legally help you because we are permitted to practice federal immigration law outside of our state of jurisdiction. Please feel free to contact me for a free initial consultation.

Sincerely,