Book Rec requests -- for my nephew

[jebbypal]

Hey all -- so i figure i will turn to the flist and see what ideas you have.

I have a nephew -- ~9yo, but reads at probably more the 11-13 yo range. With the lockdown and libraries being closed, his mom is at her wits end of finding books for him (and he prefers physical copies rather than ebooks sadly, as there went my suggestion of a lot of classics that are free from google).

Key issues:
He still has a 9 yo mentality:
-- he doesn't like much violence or horror (getting him through the bunnicula series, was interesting)
-- similarly adult level themes on sexual relationships not appropriate
-- he prefers wilderness/nature stuff more so than scifi, but will read that too

They've done all the common ones: all the hardy boys, huck finn, things like that. Some classic sci fi.

I'd managed to suggest some things that he may or may not like depending on his tolerance for girl protagonists that they are going to try -- Secret Garden, Little Princess -- as well as a humorous series i remembered my brother getting into in high school (Hank the Cowdog). Asimov

Any other thoughts/Ideas? I'm going to poke at what heinlein teen pulp might be appropriate, although with necessary historical caveats.

Thanks!!!