Draw a map for your sister about the route her kid can take--community college (which costs much less) for 2 years, and then move on to a regular college for 2 more years to get a BA degree. The cost is about 100K if live in your house. After college, he/she can move on to graduate program, in science, which is almost free. 5 years, jobs and green card, then he/she can finally set down in the U.S.. So 15 years in mind. If he/she is lucky, marry an American, the route can cut shorter.
Now it is the 100K, where it comes from. How much you can provide? Give a certain number. You can give the kid options--if go to college in China, you can provide the same support. After college in China, he/she can come to the U.S. for graduate program, and if in science major, may be totally free.
I understand you. I partially supported my sister's son who is graduate this year. I am going to completely support my brother's son next few year. Luckily, none of them asked to come to the U.S..
