This is eteranlism, not buddhism.

Causing suffering and death on other conscious beings makes you grow old and die. Refrain from causing suffering and death and you can make yourself immortal. And just to clarify, I do mean actual physical immortality where you live forever in the physical body that you inhabit; none of this immortal soul or immortal consciousness nonsense, I mean immortal physical body.

Let go of Birth and Death. Let go of attachment to the body living forever and all the fear that impossibility causes. Then you will see the deathless. Which is also the endless. Because it is beginningless.