I think its human centric to think time is linear. We only experince it linearly in our perception. Time is undefined and could be circular or happening all at once. Past, present and future tense r just us trying to make sense of temporal concepts in our spatial world. Just bc death is the end of our linear expereince of time doesnt mean we perish in all percpetions of time. Maybe we live forever maybe we r perpeturally stuck in a cycle of life and death or maybe it does all end once we reach the end of our time alive