I think most likely his green card might got cancelled when he re-enters the US custom unless he's really lucky and won't got caught that he's left the States for so many years!
You better consult with an American immigration attorney before he comes back! Good luck!
What is 2A? 其實不嬲如果分開兩地去申請都要9-12個月.我申請嗰段時間個個都係差唔多進展.你可去www.visajourney.com. Very useful information. 好多人話先入境後申請會快d.俾我再揀我都會咁做.咁耐唔見一d都唔好受.不過都慣了.你都加油呀.一個人照顧囡囡一d 都唔容易
我哋所有嘢都係自己搞,冇搵lawyer