I have no brothers.

(not any brothers, there might be more than one, depending on the context)
I have no brother.

(not a single one)
I have no (any) brothers.

(as both "no=not any" and "any" are
determiners, you cannot use them at the same time.)
I have no (any) brother.

(ditto)
I have not brothers.

("Any" is used, especially after "have", in questions and negative sentences. So, the correct sentence should be "I have not any brothers. Here, "have" is used as a verb.)
I have not brother.

(ditto)
I have not any brothers.

(ditto)
I have not any brother.

(ditto)
If anything wrong , would you correct them? Pls.