My mother's friend's husband is a math professor at a university in Kansas. A major complaint of his is students coming in who aren't able to add fractions.

So I don't see the big qualitative difference between complaints about bottom-end Chinese college students and complaints about bottom-end American college students, no.

If it's of interest, I looked into gaokao test scores a while ago and the cutoff for being admitted to a Chinese university lies around the 40th percentile. The schools are officially divided into two tiers (obviously, there are finer distinctions you can make), and the cutoff for the higher tier is around the 80th percentile. So a large number of Chinese universities should have almost the entire student body within what you might think of as an IQ range from 96 to 112.

Your mother's friend's husband is a math professor who complains about the quality of Freshmen entering into a math course, therefore the quality of computer science students in the United States are on par with the one's in China. Do you see a problem with this logic?

I took a freshmen level C/C++ class in community college as a requirement to get an Associates in Science. All we did was compile. We didn't learn any high level CS theory.