The only sins that matter for our personal salvation is the sins we personally commit. The only penitence we are responsible for is our own personal penitence. The only apocalypse that we should have our eye on is our own, personal apocalypse.
The modern Church understands that depression and other psychological disturbances that might lead a person to suicide are true illnesses, which can significantly mitigate both a person’s understanding and free will.
Moreover, even if a person’s death seems quick, with no time to repent before the end, we have no way of knowing what happens between their soul and a merciful God, who wants to bring all of His children home to Himself.