Your student is correct. The general sense of present perfect is "present state resulting from actions in the past". It can be used to talk about experiences.
If you went to Japan and saw Mount Fuji, you could come home and say
I have seen Mt Fuji.
It does not mean that the act of seeing the mountain continues until the present. It does mean that the experience of seeing the mountain is a present experience. You could still say "I have seen Mt Fuji" 70 years later when you are an old person. You still have the experience.
So "My sister has lived in China" means
My sister has the experience of living in China.
It suggests that the sister doesn't live in China now, otherwise you'd say "My sister lives in China".
Your student could have said "My sister lived in China until 2015". The past tense is possible but not required. Moreover if you say "My sister has lived in China since 2015" that does mean until the present time. The phrase "since 2015" changes the meaning greatly.
There is an implication "My sister has lived in China" suggests that this is a special experience that she has. It would be somewhat odd to say of a native Chinese person that they "have lived" in China.
So your student is broadly correct.