I always hear people say there are or there is, for instance, when I say there is a boy, can I say there has a boy? There are two men, can I say there have two men? In my country, my teacher said we shouldn't use there has or there have as these are grammatically incorrect, we need to say there is, there are in any time, is it correct?
But in terms of a Cantonese speaker, he is thinking of the verb 有 which is commonly used in that language to mean "il y a" or "there is." I think it's best to tell him his teacher is right, and not to be one of the millions down there uttering things like "Here, have many people."
The important thing yiuho is to remember that the "THERE" in the phrases there is, there are, there was, there were do not mean 里邊, it is just part of the phrase.
This is why we have it twice if we mean 里邊: There are many people there. There are many students here.