your friend is eligible for applying for change in status as soon as he gets married. since his spouse is us citizen his interview will probably be in 4-5 months (from my friends experience). as soon as your friend applies for green card his F1 status will expire but he will get to stay in this country until the interview decision. if he gets regected for green card he will be deported and will not be able to come to usa for several years(hopefully it does not come to that). i think you can get permission to travel until your interview. you can just go to uscis and spend 4-5 hours. they have everything you need. after getting married you need to file I-130,I-485,I-693(medical), (affidavit),(biographical informations), and supporting documents to missouri service center i think i am not sure you can check uscis website. then if they think you have enough supporting documents then they will call you for interview. here are some links that would be helpful to you if you google "family based green card" you can find plenty of website. You do not need lawyer you can do it on your own. dont forget to take alot of picutres and send alot of e-mails you will need that to prove your true marriage. http://www.uscis.gov/portal/site/uscis/menuitem.5af9bb95919f35e66f614176543f6d1a/?vgnextoid=5993da568324e010VgnVCM1000000ecd190aRCRD&vgnextchannel=4f719c7755cb9010VgnVCM10000045f3d6a1RCRD http://www.immihelp.com/greencard/familybasedimmigration/index.html