For non-scary ones I wouldn't go for EB Adventure series. I'd say they were her most scary series. I remember the point where they're being chased by enemies (terrorists) with guns and Bill says "Don't worry, they won't hurt children..." and you realise that firstly he's saying he will get hurt and secondly, it's probably a vain hope of his, because they'll use the children to get Bill to do what they want.
Older books if you choose carefully may suit him well.
For Enid Blyton ones I'd go for:
The Secret Island (children run away and live on an island)
Wishing Chair/Faraway Tree
Some of the short stories
Noel Streatfield has lots of non-scary stories, although more girlie, as in the main character is almost always a girl. Try Curtain Up (Theatre Shoes), Party Frock (Party Shoes), White Boots (Skating Shoes) or Tennis Shoes maybe.
The Swish of the Curtain by Pamela Brown is another that is not scary at all.
What I found with my dd who was similarly "nothing scary" was often the best way to work it was to read the first chapter or two together and once she was into the story, she was fine.
Edited to say: Sorry, I see you wanted audio books. I doubt these would be in audio, sorry!