Sorry to hear about the problems your grandson is having.

I would recommend taking a look at information posted by the Pfeiffer Clinic in Chicago on biological underpinnings of aggressive behavior and protocols that can help. Often they have high levels of heavy metals and behaviors can improve with a dietary and nutritional protocol.

Often aggressive individuals cannot eat the convenience processed foods which will contribute to overall toxicity and trigger aggressive behavior - sometimes a special diet that eliminates artificial colors, flavors, sweeteners, and fats - and is low carb and low sugar can help - what's good to eat are lots of dark leafy greens (like salad greens) and fresh vegetables can make a huge difference.

For example, a kid I knew who was about to be taken away by the state authorities because he was so aggressive turned around dramatically for the better when they started giving him Vitamineral Greens by Health Force which promotes gentle detoxification through whole foods and also contains enzymes and probiotics needed for digestive health (no I don't represent them or make money from them).

There is genetic testing that can be done through genetic testing companies like 23andme.com that may help to inexpensively reveal genetic issues in metabolism that can then be corrected through supplementation and diet as well.