As for the SM afterschooling, I gave up on asking DS to work on it after a long day in school (he has problems with writing too) and it takes forever to get even one page done in a day. So, my creative solution to this is: he works through the problems verbally and I scribe for him. This way, we get 4-5 pages done in one sitting while I can correct him as he goes and we review concepts while doing work. We have gone through one whole level of SM books (including IP and CWP) this way.
this is a good idea. I had to do this a couple days ago because he simply refused to do it. I wrote on the sheet that I scribed for him so that the teacher wouldn't think it was his handwriting (I have been telling DS the "Singapore Math" is his homework along with the other sheet, even though that really is not the case).