What I love about Dune is the incredibly thoughtful and comprehensive description of the whole desert planet and how humans can find a way to live in such an inhospitable place.
I recommended Dune to my older daughter when she was about 13. Her opinion on Dune (but then she read it just about at the same time she read Winter's Tale & Monte Cristo, which have remained some of her favorite books, now 4 years later), was that it was "OK", compared to these others which really captivated her.
The beginning of Dune is very violent, very intense. And it only lets up a little once about 200 pages into the book when our hero is just about out on his own. (That's often why the violence occurs early on, even in Disney. Have to get rid of mom and explain away dad so hero is forced to be brave and we can have a plot. But in this case, the beginning is quite elongated, full of betrayal and torture, and sad.)
The plot is kind of like Asimov's Foundation Trilogy, except that (perhaps because Asimov's characters are much less lifelike) Asimov is much less in-your-face violent and Asimov's women are -- fifties women, which is to say, extremely stereotypical. OTOH, for an 11 year old, maybe he should read the Foundation Trilogy first and then Dune?
And, finally, Dune is the first in, like, a series of 5 or so books. The first book doesn't actually end with any finality. AND, I really, really, really detested the sequels. Can't remember why, but I know I never got through even the first sequel. SO, I have no idea what happened after the first book.
My advice is that if there are other books on your list, I would probably postpone Dune for a while.
For an 11 year old, I would probably opt for Asimov over Frank Herbert. I really did LOVE the I, Robot stories and I think they raise interesting questions about the relationship between people and technology, even today. And the Foundation Trilogy, with the caveat about the women.
In fact, you might want to look into some of the anthologies of classic science fiction. (But reading those was what got me into reading Harlen Ellison and Kurt Vonnegut and they are probably NOT books my mom would have wanted me reading. But she was like me. I do not forbid my kids from reading anything, I just sometimes divert them toward something else ...)