The Sequester spell says:
If the target is a creature, it falls into a state of suspended animation. Time ceases to flow for it, and it doesn't grow older.
Both "suspended animation" and "time ceases to flow" are not game mechanics terms.
Is the creature able to perceive its surroundings? Is it able to take actions and reactions? If not, can you say the creature is unconscious or incapacitated that way?