Translation of "Incompetent" in Japanese

The world is full of incompetent doctors.

世の中は藪医者だらけ。

When Davout got into a row with Marshal  Murat, whom he regarded as incompetent,  

ダヴーが無能だと見なしたムラト元帥と列を作ったとき、

After the death of my father, it became clear that my mother was incompetent at handling the family finances.

父が死んで以来、母が経済的には不具だということが、露骨に分って来ていた。