The most important factor is how he got here....If he entered Legally, (Proper visa, inspected at the border) then just overstayed his visa, the best option is to marry in Calif, then petition him for citizenship and adjust status...form I130 and I485. Please check out WWW.USCIS.gov... This will get the process started to get the permanant residency card (Green card)

If he entered the country illegal, without proper authorization, then the situation is much different. An attorney would be best to advise you if that is the situation.