Walmart and other stores that sell bikes have cute helmets that you can get for him.

His problem is not likely psychogenic. It is more likely idiopathic. Psychogenic means he causes them from withing his head/thinking. Idiopathic means the doctor does not know why he has them. Doctors rarely use the term idiopathic because it means they do not know something. Another term used is somatic or somatoform. It means real but of unknown origin. Psycho-somatic or psycho-somatoform which means caused by a psychological cause. Some docs use the last two interchangeably but in error.

Docs and mild head injuries are a bad mix. Do you homework and you will likely learn more.

The personality changes are his injury. If you can, try to help him understand that he is safe and secure. I believe many of the personality changes are the brain over-reacting to a sense of confusion. I have undergone personality changes a few times after head injuries.

If he has regular friends, they need to understand that his outbursts and other abnormal behaviors are his brain messing up and that they have nothing to do with how he feels about/toward them. .

If you want to PM or email me, i will give you some suggestions for these struggles.

I went through this at 10 years old. i know how much of a struggle it can be.

My best to you.