Not many games manage to tell a story as convincing as Brothers: A Tale of Two Sons. The main characters set out on a fantastic journey to save their father, who has fallen ill. During the short three to four hours it takes to play through the player bonds with the brothers and their dire situation, while experiencing breathtaking vistas, heartwarming scenes, and some really dark material at points.
I played through the game myself before deciding to sit through it while my seven year old son did. I helped him undertand the dark parts and was pleased to see that he understood and accepted - and even appreciated the deeper meaning of the game. He went through feelings like pride, joy, sadness, wonder and quite some thrill. At the end he cried because of the dark beauty of the ending - and we talked in length about why not all stories can end as well as we would have liked. It's been two days now since he played it, and he says it's his all time favorite game.
To me that's worth gold. Brothers contain almost no violence and absolutely no glorification of violence. The brothers go through their ordeal by solving puzzles and move over, through or around obstacles in ther way. There are some horrific scenes that will put many parents off involving a man trying to hang himself because he's lost his family in a fire, and later a field of dead giants bleeding up a river. But in my opinion it's justified by the way it's presented. It's honest and without pretention. It's like old fairytales. It has its obligatory darkness, making the story more involving.
I'll gladly accept that I might be in the wrong for letting my son play it at his age. My justification is that the beauty of the overall story, and the way that the story is told as a non-violent videogame, makes it acceptable.
If your child is emotionally mature, and you're willing to take the journey with him/her - do it. If your child is twelve or older - let them experience the game on their own. The end is so strong and emotionally engaging that they'll try to tell you about it for hours, while feeling the value of family ties for much much longer.