Here is an example (former ESE teacher talking)
Instead of write your spelling words 10 times each...pretest and only work on the ones he doesn't know...also practice using backwards chaining. Say the word is chain.
*Chain
Chai_
Cha_ _
Ch_ _ _
C_ _ _ _
_ _ _ _ _
You study the word and then cover it with an index card...fill in the blank on the next line and always check your work with the original word. Study cover the top two lines. Fill in two letters...check with original. Repeat steps.
Doesn't take that long to make backwards chaining worksheets...but we always did them on the computer (making font size big so the kids could fit their letter on the line) so we always had them from year to year. If you know the words you could make them for the teacher.
Modify amount of problems....so if there are 20 math problems, assign odds and then if he has extra time start back up at the top with the evens...teacher grades number correct divided by number attempted no penalty for blanks...with the idea that the child works diligently and isn't taking advantage of having less assigned.
Let me know if you want more ideas.