According to my dd – mega-LMA lover – Little Men yes for 10.5, if he is an advanced and cultivated reader. If he’s not ready, it’s better to wait till he’s ready. Don’t rush the good stuff.
As per your second question, yes you really should read (or at least listen on audio) Little Women. Jo’s Boys and Little Men are sequels (with LM coming before JB), with the characters having been introduced and developed within Little Women.
One could probably enjoy them as stand alones, but there would be a deeper, missing element. Kind of like walking into a movie half-way through: you may still enjoy the remainder of the movie, but you’ll have missed important info. about characters and background that’s important for a fuller experience.
HTH