If he entered the US unlawfully, under the current immigration laws, he is not eligible to adjust status within the US. He would have to go back to his home country to consular process but as soon as he leaves the US, he triggers an automatic 10 year bar to reentry, which can only be waived by a showing of extreme hardship to a US citizen spouse, which is fairly difficult to do in most cases.
Answered on Mar 13th, 2012 at 2:22 PM