I have to say, I am pretty disgusted with these teachers. I taught 7th grade, so my kids were a year older than your DS (I also co-taught several classes with a special ed teacher, so I have a lot of experience with the "unique" and the "labelled", which to me were just kids). I would spend the first few weeks helping the students organize and get used to the organization structure in my class. They each had a binder, and every time a sheet was added to the binder, we added it to a table of contents and numbered the page before putting it in the binder. We all did this together and I and the co-teacher (or in the classes I was solo, just me) would travel around to check it out. I posted the table of contents online, as well as all the sheets of paper I gave them in class so that students and parents could print them out if they went missing. Homework was kept in a separate section of the binder and checked with a stamp when needed. I realize that your DS's teachers may not be this way, but the point I'm trying to make is that this was the bare minimum I would do with my kids, especially at the start of the year. Teachers who just pass out papers and expect 11 year olds to masterfully file them away and produce them on demand are a huge part of the problem, IMO. And not asking for homework but expecting it to be turned in anyway? What are they using to request it, telepathy? I don't understand why more teachers don't get that you have to provide the structure for kids entering MS, and then ease it away, rather than just expecting them to act like they know what to do from the get. Grrr. Sorry to digress

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While I cannot advise you about testing-that is something that you and his teachers need to work out-here is what I would do:
Email both his math and his english teachers/counselor to schedule a meeting or a phone call at the least. Some things just aren't best left to e-mail.
Lay out DS's challenges
Approach it with his teachers as a "teamwork" thing so that all of you, working together, can make it happen
Include your DS in the meeting if you think he can handle it (often we would bring kids in towards the end to help make a game plan)
Make a game plan with all 3 of you (DS, you, and teacher)
Take the initiative to follow up with the teacher every week, just a quick e-mail to see how things are going and if there are any outstanding assignments or issues. Gradually allow DS to take over this task as the year goes on
Keep the lines of communication open
Even if there was no 504 or IEP, I would be willing to do all of the above for my students. Also double-check your school's policy for late work and work posted online in case DS loses his homework.
Good luck. My heart goes out to your DS! And you.