S.H.
5th grade.
It is a ton of changes, whether or not the child is ready.
This is a cusp, age and grade.
ie: they will be in middle school next year, in school there is WAY more homework, and WAY more expectations about them being independent, WAY more expectations about them being ORGANIZED, and just WAY more expectations. AND they are Tweens, now. 9-12 years old, are Tweens. Therefore, their bodies are changing, hormones are changing, and emotional development is changing too. TONS of things, for this age and grade... to be dealing with.
My daughter is in 5th grade. And she is 10.
And ALL of her classmates, are going through ALL of this too, what I mentioned above.
My girl has SOOOOOOO much homework. Daily. It is crazy. And on top of that, they have ALL of the other things to deal with, which I mentioned above.
Again, even if they are not ready for all this, they are having to do it.
MANY of my daughter's classmates parents, are also saying the things you are saying. Because... the kids are overwhelmed. AND the 5th Grade Teachers are telling the kids regularly, that they have to be READY for 6th grade... because the expectations will be, higher and more.
Talk about pressure.
Your son, is not, unusual.
This is a common malady... of this age and grade.
Personally, I would NOT punish him, unless he is purposely making trouble.
Because, at this age juncture and grade... a kid NEEDS to be able to KNOW... that his parents are there as a shoulder... so that, once they get to middle school... they will not ice you out of their lives.
THIS, is a critical age and grade juncture.
With my daughter... I TELL HER, that I understand... this is a hard year all around. I help her express herself, help her to think of ideas to organize herself, I understand she is under so much pressure and so when she has a little lull in homework... I LET her just hang out and relax. I don't pressure her with MORE stuff or MORE demands at home. I LET her talk to me... to tell me ANY and all things that are bothering her this year. I explain to her, about how she is a TWEEN now and what that is.
The point is: at this age and grade, you need to talk WITH your son, talk with him about lots of things. So that, once he gets to Middle School he will know that you are an "ally" and not an "adversary." Not that you are a buddy... but that you are a parent that is there for him.
Because, once they are in middle school, TONS more pressure, will be upon them.
BUT the thing is: EVEN if you verbally tell your child to be more organized, MANY kids this age, DO NOT KNOW HOW to be more organized. SO, the parent must help them, "learn" how to be more organized. Before, 6th grade. ie: this can mean, getting them a BIG ol' desk calendar and multicolored highlighter pens, SHOW him how to write down his assignments and due dates per class or per subject or per teacher. Get him the tools needed to be more "efficient." ie: highlighter pens, post-it pads, a desk calendar, etc. Kids do not have inherent skills at automatically knowing how... to manage their time either. So, BEFORE he gets to 6th grade, help him and give him tips. So he can practice. THIS is what my daughter's 5th Grade Teacher, ALSO tells the parents. And they don't have classes in school on organization, either. So then kids flounder.
And yes, because 5th grade is MUCH harder and with tons more expectations and tons more homework. So, teach him the skills to manage his time and assignments, better.
BEFORE, he gets to 6th grade.