Well they increased the length and sadness buffs sometime back because simmers asked for it. It really isn't very easy to override after a death anymore with just environment. There are reward potions you can buy in game using reward points.. moodlet solver. There's a sadness alleviation lotion that you can make from the Herbalism skill that comes with OR and there is also a potion your scientists can make that might help but not sure as I haven't made if for awhile.. think it's called a need fixer but might give you a good buff too.. don't remember.
Personally I'd just give them a spa day soak and do some yoga or something else that makes them happy or distracted and muffle the sadness buff for awhile. To me that can be considered realistic because although you might have fun and laugh after a death and enjoy things it's still there heavily in the background for awhile.