I want to remember...

the spontaneous development of the written word coming from his hands.  Asking about letters, spelling, numbers, time and dates.
Looking at a word I've written as a reference and copying it legibly the first time.  His smile of satisfaction, his sense of pride and accomplishment. 
How this all just arrived without any prompting, coercion or specific training, it just emerged.
It was just time for him to write.  Amazing.