Op my DS is 7 and still cannot read very well. However, he has severe language difficulties and this impacted on his ability to learn how to read. But ! And it's a big but ! DS was not taught to read when he was in reception at his mainstream. The teacher and the therapist at the time (wrongly assumed that he wouldn't pick up during the phonics lessons so he was always out of the phonics lessons). They advised me to wait till he was more verbal. I took their word (stupid mistake!).
DS moved schools...a specialist provision and they were the ones who encouraged me to teach him to read as they were doing it too. But it's still a slow progress for him.
So yes think about moving schools, but one thing I have learnt is that to never rely on a teacher/school to teach your child. Some children thrive without getting much input from home and just learn very quickly by just being in school. The other half of children are not like this and do need extra input at school.
I taught DS to read and I was astounded how he picked it up ! Anyway... it's never too late to learn how to read plus the summer holidays is your friend right. The best resource I brought for DS... was the "The Jolly phonics Handbook". Which also provided lots of photocopied resources I can use. I spent 15 mins a day going through the lesson which is provided in the jolly phonics handbook. Majority of that time went on going through and learning the 42 (or 44) phonetic alphabet.
Decidable books are really good too !
YouTube is also good at giving you ideas. DS was stuck in the blending stage...could hear the word when I blent it... but didn't if he blent it. Looking at good old YouTube... I realised I was teaching him to blend wrong
. Now his thriving.
Keep reading books (every night)... he also needs to understand what his reading...e.g. Who is that man ? What happened....Why did the boy hurt Jim. Focussing on the 5 W's (who, what, where,when and why) and expanding DS interests (to whatever interested in the story) gave me a structure of what I needed to be focusing on when reading. This also later follows on to guided reading. But when reading to him and focussing on the 5Ws... don't make it sound like a test or ask too many questions...make it as if your figuring it out together..e.g. "Oh look DS ! What on earth happened to Reuben ?! (Pause) Silly Reuben he fell down the stairs and hurt his knees".
Rhyming books are also good. Tar Heel reader is a good free book resource... not the best visuals but it's simple, easy and your DS may enjoy it.