Paradise was made by the same designer as Syberia. But it has a much darker story, which is told in a way that makes it rather hard to get into. I thought it was well-worth playing, but I know many people disagree. (Be sure to use the patch if you play this one; the original release was awfully buggy.)
Secret Files: Tunguska might also be similar, though the puzzles are harder. The plot is a rather unimpressive conspiracy story, but it's still a rather pleasant game to play (with great graphics).
Keepsake is an OK game, focused on logic puzzles, within a beautiful magical castle. I personally didn't like the gratuitously-emotional plot, and thought the puzzles really got over the top near the end, but you might want to look into it.
And The Longest Journey might be a great, great choice (it's very dialogue-heavy though, so beware if your mother might not like that). Dreamfall is real-time 3D and tends to move a lot, so it's probably not a good choice for a person with a motion-sickness problem.
