Isn't it ironic Richard parker?we are living in the hell yet we afraid of immortality.

There are a few ideas at play Richard Parker has become worthy of Pi's musings about spirituality and the afterlife. This particular quote reflects Pi's devotion to matters of religion. I think Pi's point here is that we fear the afterlife, immortality, more than the trials that we face on this earth. In Pi's case this question is especially compelling. This sounds very much like Hamlet and his undiscovered country speech,

"To grunt and sweat under a weary life,

But that the dread of something after death,

The undiscovered country, from whose bourn

No traveller returns" (Act 3)

So, this question of the afterlife possibly not being such a picnic is an old one. The irony of Richard Parker ending Pi's life at any time is also interesting to note. Even though Pi and the large cat are living in a hell, drifting through the Indian Ocean on a raft, they still fear the afterlife; they still fear being judged by their maker. I say "they" because Pi is obviously personifying his tiger.