Recommendation please for short stories book for an 11 yr old

[LiveLifeWithPassion]

It's for a reluctant reader (boy) who seems to get a bit overwhelmed by the sight of a 'long' book.

Anyone have any ideas please?

How about 'world's worst children' 1 & 2 by David Williams?

*Walliams

The 13 Storey Treehouse series is popular.

Thanks for those.