My father had been in the U.S. for 20 years under temporary resident status. Back in 2005 he was denied an extension and was told by the USCIS officer that the only way he could become a permanent resident was if a US Citizen son or daughter petitioned him. I am about to become a citizen filing under military service. After my father was denied the extension he was notified a short-time after that, that his mother was ill. He left the country voluntarily and has been out for almost 7 years. My question is.. what problems could we encounter when I petition him under I-130 or what steps should I take? Any advice? Of course I am planning on seeking advice from an attorney, but want to have an idea of what I should expect.