Life is not a celebration.
That's what Lord Rama is establishing through the Vairagya-prakarana of Yoga-vasishta.

Childhood is a period of helplessness, fears, and anxiety.
Youth is fraught with dangers, risks, and is a period of reckless living.
Old age- diseases, dependence.

Where is the time to celebrate?

The lord continues with the old age: as soon as old age sets in, it blossoms rheumatic diseases and respiratory problems in the body.
Like how the rising moon blossoms the Water lily.

Ash gourd, you know the vegetable ash gourd when it becomes ripe, its skin gets a white powdery coating.
That's when the farmer knows that it has become ripe.
Then it is cut and eaten.
Same with man also.
The ash gourd-looking head when it turns grey Kala knows it is ready to be consumed.

Like how a flooded raging river would take away the soil between and beneath the roots of trees standing on its banks and makes them fall, this is how it happens in old age also.

Old age is a howling jackal that has come into the forest.
The sound of coughing, lamenting, complaints.
The peace that prevailed in the forest is gone with the jackal's arrival.

The flame of life is still there in the body.
But it is like the flame coming from firewood that is wet, smoky, dark, and any time ready to extinguish.

Even the light in the eyes turns smoky and after some time it can go off fully also.
A creeper with white flowers and fruits is bending down because it is unable to bear the weight.
This is how the old man's body looks like.

Death can come any time like an elephant, pull out the plantain any time and throw it away.

When a king goes somewhere his retinue goes in front.
Here the retinue is diseases, worries, anxieties of old age, and the king- death always follows them.

There are those Sages who are all the time living in the caves of high mountains.
No enemy can ever come near them.
But even them old-age and death approach and destroy.

A house after heavy snowfall; doors, windows, everything is blocked with layers of thick snow.
The occupants of that house can not move out.
Their movement is restricted to the inside of the house.
That's how the sensory organs are inside the old man's body.

Man gets a third leg when he becomes old, the walking stick.

I don't trust this body, says Lord Rama; old age and death are inevitable destinations for this body.

First old age and then death.

How can you trust this body?

Life still wants to hold on to the body even after reaching this pitiable and miserable condition.
What use is it of?
Nothing can be achieved anymore.
Still, life holds on to it.
With some false hope.