Today's Free App of the Day is Helidroid 3D
This is a game where you control an on-screen remote control helicopter and must fly it places and achieve missions. It's well reviewed as far as game play. I think the grandson would enjoy this.
10 of 17 reviews are four stars and above.
These apps are compatible with the original Fire and with my Fire HD 8.9" 4G. To tell if an app works for your Fire HD or other Android device registered to your Amazon account, click on the above link and look on the right side of the web page. Amazon will tell you if it will work with your registered device.
Also check out the other digital deals from Amazon, including great deals on MP3s and videos: