why was her mothr's face is looking like that of a corpse?

The poet was going to cochin from where she had to board an aeroplane for her journey back home. The poet's mother was sitting beside her in the car.She was travelling with the poet to see her off at the airport . As they were travelling, the old woman dozes off and the poet looks at he intently she notices that her mother is now old and pale.she looked like corpse ( dead body ) because her face was colourless and seemed to have lost the fervour of life .