Too often, ARs do not follow the correct process. What should happen is:
Updated advice and information must be circulated at least 2 weeks prior to the AR meeting. This is important for a successful AR.
Then you have the AR meeting.
Within 2 weeks of the AR meeting, a report must be circulated.
Within 4 weeks of the AR meeting, the LA must inform you if they propose to amend or not and if they are, they must send the amendment notice at the same time.
Then if the LA is going to amend, the LA must finalise within a further 8 weeks, so max of 12 weeks from the AR meeting.
Before the meeting, go through the existing EHCP, existing evidence and the updated advice and information circulated looking at where amendments need to be made. Pay particular attention to PfA provision because that is often overlooked by LAs.
From your post, it doesn’t sound like the school is meeting DS’s needs. It is far more likely to be can’t engage rather than won’t and a different approach is needed. The provision detailed, specified and quantified in F of the EHCP should be provided. What is in F? Is it detailed, specified and quantified, or is it vague and woolly? Communication can be included in F, is it? As can things like homework adjustments/support - no homework, reduced homework, adjusted homework, support with homework during school hours or at homework club…