My beautiful grandson

Hi,
My name is Wendy and I’m looking for some help/advice 
I wonder if you can help,I have a grandson who is almost 6,he has the sweetest nature,he was non verbal until around 3-4 and we had several private speech therapy sessions for him,from early age we have realised he’s on the autistic spectrum which is absolutely fine as we don’t let it define him,he’s also in mainstream school,he is highly intelligent and will tell you from flash cards what every single flag of the world is,he also loves maths,we are still waiting results of an assessment he has for autism some months back too,over the last year or so he has got upset over some odd things to us but clearly trouble him,big shop signs,doesn’t like shopping centres because of the signs on the windows,doesn’t like the tele being off as the dark screen scares him,interactive whiteboard at school makes him really upset,the last few weeks he can’t cope with looking at names,especially if we’re out and a shop has a carousel of say Xmas decorations with all names on we have to leave the shop as his too distressed by them,he’s birthday is coming up and he doesn’t want a name on the cake as he’s scared he says,in the last 2-3 months (he may have had them before but was non verbal and now it’s happening every couple of weeks and usually after we’ve been to shops,which he always agrees to as we won’t ever force it but he then gets upset once there) he has had a headache which starts with him needing a proper toilet,then he complains of headache which he is then sick and then he is fine after a bit of rest but then the school makes him have 2 days off after his sick,he had a normal eye test yesterday and he has 20/20 vision,my friend has recommended we get him tested for irlen syndrome which we have and he has an assessment on 18th Dec,I tried reading to him last week and he put his hand over my mouth to stop,he doesn’t want to do the reading or writing tests in school but gets 100% on maths,we just want to make his world as easy as possible for him,is this a common story as we’re obviously very new to it all and any advice would be really appreciated 
Wendy Eastwood