This is a polite way of saying that he has sexual relations with his father's wife. Some languages use more direct phrases such as "has sex with his father's wife." (See: [[rc://en/ta/man/jit/figs-euphemism]])
# he uncovers his father's nakedness
Here the idiom “uncovers … nakedness” means “disgraces.” Alternate translation: “he disgraces his father” or “he shames his father” (See: [[rc://en/ta/man/jit/figs-idiom]])