Allah is the one who created you from weakness, then made after weakness strength, then made after strength weakness and white hair. He creates what He wills, and He is the Knowing, the Competent (Ar-Rum, verse 54)

Growing old is not an illness that can be treated but its a phase of life that cannot be avoided

A person getting old is a part of destiny that Allah has written for him. If you notice the sequence of growth as mentioned in the above verse, first come weakness as a new born baby, then grown up strong man and then once again a person becomes a weak old man. An old person turns like a newborn baby as he is totally dependent upon others for his walking and moving. He loses  his teeth and like a baby he cannot chew. It is not possible for any person to save himself from old age. Once you are out of the womb of your mother, nothing can stop you from aging. One may hide his age by dying hair and applying cosmetics but can’t stop himself from aging.

Elders are supposed to be honored, respected, helped and given first preferences.