My DS has just started Y1. He'll be 6 in a couple of months. It is such a struggle getting through his reading books each week. He rolls around on the floor, refuses to look at the page, talks about random things, makes up the words. We finally agreed to take it in turns reading sentences and he can do it, but started yawning within a couple of pages and genuinely really struggled to focus long enough to get through it. It's an 8 page book.
He's a bright kid and doesn't have any behaviour issues, just when it comes to reading he has a block.
I'm not sure on the best approach.