His father is even more eccentric, speaks his mind, and has no manners at all.

speaks 是动词 speak 的第三人称单数形式，意思是"说话、表达"。 his 是形容词性物主代词，指"他的"。 mind 的意思是"思想、想法"，在这里指个人观点或看法。 speaks his mind 是一个固定短语，意思是"直言不讳、说出心里话"，指毫无保留地表达自己的真实想法。