Tourist visa to the US is good for 2 years?
Thats news to me....
He only needed to marry his girlfriend, if she is a US citizen. Then he could apply for the green card right away:
Persons married to US citizens are considered "immediate relatives" in the immigration process and can apply immediately for LPR status. The USC spouse may file an immigrant petition (Form I-130) for the alien spouse immediately after the marriage. The alien spouse may file an application for adjustment of status to LPR (Form I-485) and accompanying requests for interim work permission (Form I-765), and interim travel permission (Form I-131) immediately after marriage.