وَإِذَا مَاتَ شَدُّوا لَحْيَيْهِ، وَغَمَّضُوا عَيْنَيْهِ
Translation: After the person has died, the jaws are secured and the eyes are closed.
Lahyayhi refers to both jaws. They are gently secured to prevent the mouth from remaining open, and the eyes are closed carefully. These steps precede the formal washing.