Hi. You need to determine if he has 245(i) protection first. Have any immigration petitions or labor certifications been filed on his behalf at any time? If he does not have 245(i) protection then he will have to leave the US to do his adjustment of status even if the petition is through marraige. You should talk to an immgiration attorney about specifics in your case before you do anything. Good Luck!
I will concur with the previous answer. You must first assess whether anyone ever filed a petition for him directly or as a derivative before April 30, 2001. If not, then you need to assess whether consular processing is a good option for him. Currently, many cases are being approved in Cd. Juarez, if the waiver is properly prepared. Please call an immigration attorney to discuss your options.
Best of luck.
Verdin Law Firm