USA, Canada / How to stay in USA without getting married? [125]

i'm not quite sure how long ago this discussion was posted or if anyone will reply but..i'm looking for some advice.

i met someone during summer this year from south africa, this may not apply to the polish forum (ha) but it seems to relate to the topic. He is wishing to stay in the united states and i want more than anything to be with him. he was in the process of applying for a political asylum but found that the process would be much more complicated than he had anticipated. He is now leaning towards marrying someone, the thing is i'm merely a student and i feel as if now isn't the right time, for me atleast. and so his plans are to find someone to marry, and then later be with me. which is one hell of a screwed up situation, i know. That, or he was interested in buying a green card if that is at all possible. Needless to say, I know close to nothing about any of this and I just want to be able to provide some sort of relief to him, and myself. I simply hope there is a simple way to go about this. His working visa expires in late November and the longer the wait, the more i feel as if the chances are growing slimmer.

I just am looking for some options, and details. If he buys a green card, what are the pros and cons? I've seen enough info about the marriage deal and that is absolutely his very last option. What is the best way to go about this?

Any help is greatly appreciated.