Isn't the PhD supervisor required to teach the student the research subject and prerequisites, in order to save time? My friend is completing her PhD comprehensive test and is going to start research.

Her supervisor is emphasising the importance of self-learning. He is saying that "I will provide the necessary resources, books, etc., I am not going to teach you anything, it is your responsibility to complete prerequisites. There are several resources over the internet to accomplish all your required tasks".

My doubt is that why can't the supervisor teach at least the prerequisites and the subject of research to some extent? 

Anyway, the literature survey and the publishing will be done by the student only. In this context, my doubt is to know whether the supervisor is bound to teach or not?
Supervisors train; they don't teach. (Albeit the distinction between terms is rather subtle.)


  why can't the supervisor teach at least the prerequisites and the subject of research to some extent?


A PhD is like an apprenticeship, rather than a taught degree (such as an undergraduate degree). Hence, supervisors are expected to train, not teach.


  the literature survey and the publishing will be done by the student only.


Actually, the supervisor will guide the student in both activities and will (likely) be a co-author of any publications.


  is...the supervisor [likely] to teach or not?


No: The supervisor has said they won't teach nor is it their job to do so. 



The supervisor is quoted as saying, "I am not going to teach...it is your responsibility to complete prerequisites," which might reference (especially in the US) taught courses that PhD students are required to take. Given such context, the supervisor may merely be explaining that it isn't their responsibility to provide any help for taught courses.