8 year old afraid of his bedroom

[nipplesofthenorth]

Our DS4 who is 8 has been having trouble going to sleep for a long time. He used to share with DS3 (aged 10) but we is now in a room on his own as he was stopping his brother sleeping. Every night he has a bath/drink/story and goes to bed for 8pm. Every night he is still awake at 10-11 o'clock. He cries, says he's afraid of his room/monsters/the attic, has no friends (not true). When he does go to sleep he sleeps right under his duvet. The fears don't relate to his brother being moved out - they've been going on MUCH longer.

We've done up his room to his specifications, got him a new bed, stuck posters over the attic hatch in his room, made sure he has a working nightlight.

Does anyone have any ideas? He is very grumpy all the time (due to lack of sleep I guess).

Oh poor little lamb, obviously having a bit of anxiety? Have there been any changes at school that might have unsettled him.
I know this is a bit random but what colour are his walls, apparently colours like lilac/purple can cause nightmares/fear of the dark?

Have you tried sitting in there with him in the evening and getting him to point out what is bothering him? Sometimes it can be something which looks fine in the light, but dodgy as a shadow - eg dressing gown on a hook.

If its monsters under the bed, can you clear it out so its easy to see the space is empty? If the attic has a door, can you move a piece of furniture in front of it?