Tanya,
Welcome to NeuroTalk. Sorry to hear about what happened to your friend.
What have you read that has you so scared about his future and yours ?
There are a few links about mTBI in the Vitamins sticky thread at the top. Look at the bottom of the first post. They will help you understand.
In the short term, I suggest you try to be a quiet steady presence in his life. If he is confused about you, you could tell him about specific times together, maybe a weekend. His memory about you may come back. The brain can be a finicky organ. It can forget something but give it just the right clues and the memory comes flooding back.
My wife will ask me about something and I will respond that I don't have any memory of that situation. She can start telling me about it and halfway through her comment, my memory suddenly kicks into gear and remembers.
The vitamin regimen in that sticky post will help his brain battle the toxins from the injury.
Could he have been a victim of "The Knockout Game" ? Street kids attack and try to knock out random unsuspecting people just for the thrill. Sometimes, they video it for YouTube.
If you give him some time and ask us questions as you go along, you will learn about a hidden part of the population. We are the invisible wounded. Understanding this injury can broaden your ability to be a part of the lives of others with mTBI. Many soldiers who have been in Iraq or Afghanistan have varying degrees of this same set of injury caused symptoms. He is not alone and you will not be either.
You may be of help by finding a brain injury support group to attend.
www.BIAUSA.org has a referral to local chapters and support groups.
What city and state are you both in ?
Please hang in there. If you are the only one to seek understanding, you may be the way his family learns about his injury. Pass the links along.
My best to you.