Having worked in primary schools for over twenty years, mostly as a TA, I am afraid I find your attitude one of the most disturbing - and, possibly, disturbed - that I have ever come across.
Yes, of course parents should be supportive and involved in their children's education and activities, and most MN are just that, but I believe that this 'hot house' attitude is excessive, and as several other professionals have clearly stated, it should not be necessary.
Are you REALLY doing this only for HIM, or are YOU wanting to bask in the reflected glory of his progress? Why was he not progressing from the normal school day, as, presumably, most of his peers are? There is a lot more to school life than just 'reading and writing', and it should hardly be necessary to 'draw dots' for him to learn to form letters correctly. Unless, perhaps he has some disability, which you haven't told us about.
To me, this smacks of the 'failed dancers' who spend thousands of pounds on their tiny daughters, taking them to never ending dance classes, buying expensive, glamorous dresses, and transporting them all over the country to dance competitions, so the mothers can pretend to themselves that this is what they COULD have done, if only . . .
I am sorry to be harsh, but I would ask you to examine YOUR OWN motives very carefully, before you continue on this regime of extra work. In the long run, it could end up doing more harm than good. And are you totally confident that your own knowledge of HOW to teach a young child, and what methods are used in schools is fully reliable?
I am also forced to wonder what your own school days, and experiences were like.
Do think about it carefully.