Sims don't sleep

@Nimbindi I was having that happen to a couple of the Sims in a household once. I had to put in a whole string of sleep commands and keep re-adding them until they got enough sleep. (I also had this issue with fun and social (and maybe sleep - I can't remember) with the two children in a household where there was a crash of the parent's rocket ship.) A 'nightmare' for sure. I was afraid they would die of exhaustion if I just left the game without them getting some sleep first the were so exhausted! In my case the glitch went away. I can't remember exactly the solution, but these are things I would have tried, so it is likely one of them. 
You can try...

• I'm sure you did this already, but sometimes just leaving the game (especially if you haven't already saved it with the glitch running), shutting down the game then re-starting it will have fixed a glitch when you re-enter the lot.
• Go to 'Manage Households' and move the sim to a new household of their own. If it is a child you may need to move an adult with them. Save and exit the whole game, then go back in and open the household and save. Next go to Manage households and re-add them into the original household and save. Now go in and see if the glitch is gone.
• You can save the household into your library, and save the lot into the library, and repair the game. See if that fixes it.
• You can try moving the family to a new lot or home. A new household move is a kick in the pants that can do wonders to 'reset' some things.

If all of these things don't help, you can reset your game &/or the sim, as @PugLove888 suggested (see thread on link below for extensive detail on the process, if you want more info on it). Or you can just do it rather than trying the other things, for that matter. In the case of the Sims in my household that I mentioned I did not reset the game and I'm still playing them successfully. They did move past it - with some help. : https://sims4.crinrict.com/en/2014/09/resetting-the-game-to-factory-settings-without-reinstalling/

@danuta720 ... I did not realize that playing a long time on the same save could cause this type of thing. That may have been my issue in those two households. Good to know!

And, of course, as @kreatora mentioned, many odd behaviors and glitching can be rooted in Mods and CC, so removing and testing those may be needed, if you have any.