Yes, I missed that. It's not your students, but their friends and family back home. Also, I now understand that those at home believe
all religion is superstition, including Christianity. Hmm. I wish I had an easy answer. I doubt what I am about to say is what you are looking for; nonetheless, I'll throw caution to the wind...
I am assuming the folks back home are materialists/naturalists, especially given the context of communist China. One way your students might help the folks back home see that Christianity is not simply another "superstition" is to first put into doubt their friends' and families' assumptions concerning naturalism/materialism. By planting doubt in the materialistic/naturalistic assumptions of their family and friends, they are making room for theism as a viable alternative (at least for argument's sake). If they can show that theism is at least an option worth considering, then the theism of the three Abrahamic religions has as unique feature that can be used to show how the Abrahamic religions (and therefore, Christianity) are different from other religions.
There are a number of ways to try and put into doubt the assumptions of a materialist/naturalist. More often than not, it will be a matter of chipping away at their assumptions with various arguments (or "possibilities") rather than a one-time slam dunk. Just one example to get the juices flowing: The materialist/naturalist might assume that all of their thoughts, emotions, desires, motivations, etc. are ultimately explicable via natural processes in the brain. But is that right? Is it really the case that their love for each other, their ability to recognize what is good, their desire to have a fulfilling life, their goals and purposes, all of it can simply be reduced to a few neurons firing off in their brains? (Keep in mind that the students are trying to plant seeds of doubt-making room for an alternative way of seeing things) If our experiences can't be reduced to neurons firing off in our brains, then what is the source of our sense of meaning, purpose, our love and desires, and so on? A loving God, perhaps? This is just one example of a possible way to try and chip away at the materialist's/naturalist's assumptions. There are certainly other ways of approach
The idea is not so much to convince the folks back home that God exists (at least not initially), but simply to put into doubt their assumptions that keep them from considering God as a viable option. If and when they are open to the possibility (for argument's sake) of God as a viable option, then they can begin to separate Christianity (or better: the three Abrahamic religions) from most other religions by putting forward the possibility that this
One God is also Creator. Here they are arguing for monotheism, and separating the monotheistic conception of God (understood according to the Abrahamic religions) from various superstitious religions (idol worship, totems, amulets, or whatever) and also from various eastern conceptions that don't think of God as personal. The conception of
One God as Creator seems almost unique to the three Abrahamic religions. Once they have done that, then they can begin to put forward a case for Christ, if they are so led.
It really is a process. Here is the approach I am suggesting:
1) Chip away at the naturalist/materialist assumptions in various ways
2) For arguments sake, put forward the possibility of monotheism as another viable option to materialism/naturalism
3) For arguments sake, make the distinction between God as Creator (monotheism) and other religions (various kinds of paganism, animism, and eastern conceptions of god that do not assume a Creator/Personal God)
4) If, at this point, the folks back home are open to the possibility of theism, then it's a good opportunity make the case for Christ. (There is no sense in trying to make a case for Christ if the recipient isn't even open to theism).
Whatever the case, and in answer to your question, if they succeed so far as (3), they have gone a long way in showing that Christianity is not just another "superstition." That doesn't mean that the folks back home have now come to faith (maybe so or may not), but at least the folks at home may now recognize the difference between the "superstitions" they are accustomed to seeing and monotheism, which includes Christianity.
So, yeah. I'm almost certain this is not as helpful as you want, haha. This situation you are referring to is complex and would take some time and commitment to really address. But if they are friends and family of your students, maybe such time and commitment is not a problem. I wish I could be of more help.