Granted, I can be kind of a prick sometimes, but now that the disclaimer is out of the way lets move on to the good stuff.
Moon, so far the texts and calls have stopped but instead of stopping there why not keep going? Instead of dropping this I would take all the info you have down to the local INS office (you said his parents dont speak english). Give them the name and make sure the family is here legally, if not REPORT THEM. I bet harassing text messeges from China are pretty expensive, dont you think?
If they are here legally you still have recourse, report the family to the case worker. Assuming the kid is under 18, he is his parents responsibility. Now they wont get deported or anything, but dont you think they would probably be kind of pissed if they case worker called them in regards to their sons activities? Personally I'd ring the kids neck if I were his parents. If it were me I would hope for deportation, I think that its the best long term solution for your troubles.