I was a primary TA / helper for over twenty years, and during that time methods of learning to read and write changed greatly. The main thing is that he is learning SOME phonics, and that he is enjoying books, and is happy to share books at home. Keep it relaxed, and if some nights he doesn't want to 'work', then don't worry.
It is little more than two years since he learnt to TALK, so he has probably learnt much more new stuff in that time than you have!
You might find this useful:
An inexpensive and easy to use book, that can encourage children with reading, spelling and writing is mentioned in the MN Book Reviews section. In “Children’s educational books and courses”, the Oxford Phonics Spelling Dictionary presents words by their initial SOUND, unlike a ‘normal’ dictionary, which is always in alphabetical order. Thus, in the ‘S’ section are words like ‘cinema’ and ‘cycle’, which have a ‘S’ sound, even though they are spelt with ‘C’.
The Dictionary is colourful and amusingly illustrated, and can be used by children on their own, or with adult support, from Reception age right up to the start of secondary school.
The review has a link to view sample pages, and purchase if you so wish.