OK, so in the finale it's implies that Gai doesn't tell Ryu he's been stabbed since that would ruin the wedding. Won't it ruin the wedding even more when they discover his corpse sitting on the bench?!
Seems like because Gai thinks he's going to die anyway, and better give his blessing before he passed on, rather than just no-show at the wedding, ruin the wedding because of it, and either way, they're still going to find out his corpse and get saddened anyway.
Why did Grey's tears make Rie's body disintegrate?