My son has a bad habit of paying no attention to me when I'm talking to him.
My son has a bad habit of letting everything go in one ear and out the other.
「息子は人の話を聞き流す悪い癖がついている。」は英語で「My son has a bad habit of ignoring people (talking to him)．という表現が良いと思います。
聞き流すーTo ignore・To pay no attention to・To let it go in one ear and out the other
悪い癖ーBad habit
悪い癖がつくーTo get into a bad habit・To develop a bad habit
アメリカ合衆国 
