My mum died and I was in work the next day. Life moves on man.
My grandmother who raised me died and I went on medical withdrawal for the entire semester of Uni after being unable to handle it.
Depends on how close or what the person was to you.
Oda saw Toriyama as his rolemodel. Given that Toriyama read OP with his kids, Oda probably had dreams of being able to share in the celebration of when OP ended with the guy. Now he has to face the fact that he can never do that. That would be a somber reality check.