Hilchos Lashon Hara chapter 8, section 1

The prohibition of lashon hara is the same whether the speaker is a man or a woman, a relative or not a relative.

Sometimes the person spoken about does not mind, because they are relatives. And someone who speaks lashon hara about a relative is not saying it to put him down, but only so that he will improve his ways. Even so, if he rushed to judge his relative harshly, and in truth his relative did nothing wrong, it is complete lashon hara.