I didn't want to respond to this until I had had a chance to look at it carefully. I really like the image. Yes, the right side is a bit empty, but to me that emphasizes the empty chair. I'm not 100% sure I like all the rectilinear angles, though. Maybe put in one larger untidy object on that side?
I also like the girl's expression and even her posture. This suggests to me that she is still in a somewhat hopeful stage, thinking that if she just looks again, the missing person will be there. Yes, move the eye just slightly, but that's a detail. I'm also sure a lot of this will get worked out in the painting stage.
I would de-emphasize some of what's going on in the sink. I get the point that in their grief, the remaining members of the family are neglecting the home, and probably once you add values and color it will push this stuff more into the background. It's just that there is so much going on around the girl's head and nothing elsewhere. I gather that this piece should be primarily about the people and that the objects only support the story about the people.
And finally, I know this is primarily an illustration about the girl and the dad is emotionally preoccupied. But even if he has glasses and is looking down, I'd love to see some hint of his eyes. I'd love to see him a little bit more developed overall, and perhaps that will happen as you work.
I really like this little girl and the way you've developed her, from her worried yet innocent expression to her hand dreamily holding the spoon (she's a lefty!) to the way she's shifting her feet in hers slippers. I would love to see this piece finished!