My friend texted me about it this morning and my first thought was that it was a hoax or something. It's surreal.
I hope his family and friends/groupmates are okay.
IIRC, he was really open about struggling with depression. Even talked about it on his radio show.
That's a tough battle by itself, but I would imagine being an idol makes it that much harder.
I've already seen a lot of netizen comments saying "oh he was successful, talented, and wealthy!" as if that makes someone immune to mental illness.