How can someone(the one who is dying) enjoy his death moment?
Yes, one can also even enjoy his death hours or last days or death moment, not by doing things pleasurable to him. But through Gyana or right kind of knowledge about life and death.
By knowing our true identity, and purpose of life and the eternal laws of nature with which everybody is bound.
With the right kind of knowledge, faith in supreme creator, being free from all material desires, surrendering to god, cheerfully accepting the changes jivas undergo throughout his life cycle etc. as told in Hinduism scripture one can stay calm, happy and unaffected even at his death bed as told throughout Hinduism scriptures.
It's very common that we face certain conditions during old age or near to death like the fear of death, necrophobia, anxiety, sorrow, grief, emotional pain, depression, sympathy, compassion, solitude, or saudade that do occur in all the human beings.
The Hindu scriptures are are giving us the solution to all this by giving us the in-depth knowledge (Gyana) about our true identity and process of life and death etc. Thus giving us the moral support and reveling the true secrets , otherwise hidden due to our ignorance.
So Hinduism scriptures urge us to obtain the right kind of knowledge and through which we can overcome all this situations and can enjoy the phenomena of death with cheerful heart.
Let's see what Hindu scripture is telling us with which we can fully appreciate death with open and cheerful heart.
Accepting of the phenomena of Death which is unbeatable .
First thing one must accept that death is unavoidable, it's certain to all living beings. And knowing and accepting this phenomena one can avoid the unpleasant situations that will arise due to phenomena of death.
Rig-Veda - Mandala 10 - Hymn 14 -Mantra 2 is telling us the exact same thing that was stated above - The Devata of this hymn is Mrityu i.e. death. In this hymn, we can see the mantras which are addressed to the person who is dead or is of old age or near to death. This is an inspirational hymn. Telling us that we will go through the same path our ancestors gone before to meet Yama and Varuna, and asking them to bless us after death.
यमो नो गातुं प्रथमो विवेद नैषा गव्यूतिरपभर्तवा उ |
पूर्वे पितरः परेयुरेना जज्ञानाःपथ्या अनु स्वा: || Rv. 10.14.2 ||
yamo no ghātuṃ prathamo viveda naiṣa ghavyūtirapabhartavā u |
yatrā naḥ pūrve
pitaraḥ pareyurenā jajñānāḥpathyā anu svāḥ ||
No one is capable of averting the laws of Yama.
And Shree Krishna is telling us the same in Shreemad Bhagvat Gita
and advising us not to grieve.
जातस्य हि ध्रुवो मृत्युर्ध्रुवं जन्म मृतस्य च।
तस्मादपरिहार्येऽर्थे न त्वं शोचितुमर्हसि।। BG 2.27।।
jātasya hi dhruvo mṛtyur dhruvaṁ janma mṛtasya ca |
aparihārye ’rthe na tvaṁ śocitum arhasi ||
For certain is death for the born, and certain is birth for the dead;
therefore, over the inevitable thou should not grieve.
Shree Krishna in Bhagavad Gita 2.22
is also explaining the reason of our death in order to revive of all above sorrows related to old age and death Shree krishna in below shloka of Shrimad Bhagwat Gita is advising us to know the basic fact, that, as a we throw out worn-garments and puts on new, so the self or Atma cast off its old worn out bodies and enter into others that are new.
वासांसि जीर्णानि यथा विहाय नवानि गृह्णाति नरोऽपराणि।
विहाय जीर्णा न्यन्यानि संयाति नवानि देही ।। BG 2.22।।
vāsāṁsi jīrṇāni yathā vihāya navāni gṛhṇāti naro ’parāṇi |
śarīrāṇi vihāya jīrṇāny anyāni saṁyāti navāni dehī ||
Just as a man casts off worn-out clothes and puts on new ones, so also
the embodied self casts off worn-out bodies and enters others which
Knowing our true nature - we are not the body but the Atman or Brahman itself -:
Hinduism believes that there is Atman (soul, self) in every being which is the essence of an individual. Atman, in Hinduism, is considered as eternal, imperishable, beyond time, "not the same as body or mind or consciousness, but is something beyond which permeates all these". Atman is a metaphysical and spiritual concept for the Hindus, often discussed in their scriptures with the concept of Brahman.
The Brihadaranyaka Upanishad describes Atman as that in which everything exists, which is of the highest value, which permeates everything, which is the essence of all, bliss and beyond description. In hymn 4.4.5, Brihadaranyaka Upanishad describes Atman as Brahman (universal absolute; supreme soul), and associates it with everything one is, everything one can be, one's free will, one's desire, what one does, what one doesn't do, the good in oneself, the bad in oneself.
This theme of Ātman, that is soul and self of oneself, every person, every being is the same as Brahman, is extensively repeated in Brihadāranyaka Upanishad . The Upanishad asserts that this knowledge of "I am Brahman", and that there is no difference between "I" and "you", or "I" and "him" is a source of liberation, and not even gods can prevail over such a liberated man.
तदिदमप्येतर्हि य एवं वेद, अहम् ब्रह्मास्मीति, स इदं सर्वम् भवति,
तस्य ह न देवाश्चनाभूत्या ईशते, आत्मा ह्येषां स भवति;
tadidamapyetarhi ya evaṃ veda, aham brahmāsmīti, sa idaṃ sarvam
bhavati, tasya ha na devāścanābhūtyā īśate, ātmā hyeṣāṃ sa bhavati;
And to this day whoever in like manner k(?)s It as, ‘I am Brahman,’
becomes all this (?)verse). Even the gods cannot prevail against(?)
him, for he becomes their self.
And the understanding characteristics of this Atman or Brahman is understanding our own true nature or is our true identity. Which is Sat-Chit- Ananda.
I am of the nature of consciousness. I am made of consciousness and bliss. I am non-dual, pure in form, absolute knowledge, absolute love. I am changeless, devoid of desire or anger, I am detached. I am one essence, un-limitedness, utter consciousness. I am boundless bliss, existence and transcendent bliss.I am the Atman, that revels in itself. I am the Sacchidananda that is eternal, enlightened and pure.
This self is non destructible unlike our body which is subjected to cycle of birth and death, our true self is non perishable.
न जायते म्रियते वा कदाचि न्नायं भूत्वा भविता वा न भूयः।
नित्यः शाश्वतोऽयं पुराणो न हन्यते हन्यमाने शरीरे।। BG
na jāyate mriyate vā kadācin nāyaṁ bhūtvā bhavitā vā na bhūyaḥ
ajo nityaḥ śāśvato ’yaṁ purāṇo na hanyate hanyamāne śarīre
For the soul there is neither birth nor death at any time. He has not
come into being, does not come into being, and will not come into
being. He is unborn, eternal, ever-existing and primeval. He is not
slain when the body is slain.
Preparation through true devotion (Bhakti) and surrendering to lord.
When we truly surrender to god all our doubts, fears, sorrows and worries vanishes. We experience true bliss you make peace with death and watch its devouring power without fear and aversion. As promised by god himself.
तेषामहं समुद्धर्ता मृत्युसंसारसागरात्।
मय्यावेशितचेतसाम्।। BG 12.7।।
12.7 Of those whose minds are thus focused on me, I become soon their savior from the ocean of mortal life.
those who, renouncing all actions in me, and regarding me as the supreme, worship me... For those whose thoughts have entered into me, I am soon the deliverer from the ocean of death and transmigration, Arjuna. Keep your mind on me alone, your intellect on me. Thus you shall dwell in me hereafter.
Thus by Bhakti Yoga and surrendering oneself to god one can be free from all the fears that arise from idea of death, in full assurance that the supreme lord will take us out of this ocean of sansara safely and will liberate us or will give us the Moksha , the highest state described in hinduism, we can overcome the fear of death.
So finally this is just short answer of how one can enjoy the moments of death" ** Through spiritual experience and gaining the knowledge of self ** And this knowledge through which we can understand the death and all its spiritual aspects can be an enjoyable experience. Not the kind of enjoyment in general sense ** but a kind of different divine enjoyment ** in the form of Bliss.