If you are really interested in helping your classmate then you can follow the steps:-
1) help him/her to know/ understand what is been given as homework, then he/she can do the homework on their own.
2) you need to make sure that he/she understood what was told by their teacher- lesson explained today. then they wont have any fear or any doubts on how to do the homework.
3) converse with them only and only in English, though it may be tough for them to cope up with your English but they will at least understand what you are saying. which can has possibilities that they will also answer in English.
anyhow the person themselves should have interest to take your help, pay attention to what you are actually trying to make them. as English is the basic in our daily lives.
if they want you can check your both answers - cross check your both home works.