We have stayed in touch all these years as friends and recently his wife died. At first it was by letter but since the internet was invented we have been in touch on a daily basis
So you have actually been in touch with him for 30 years. That does make it more understandable. When you say you've been in touch on a daily basis, how? By phone, text, or have you had video calls? That would of course be the best way of communicating as you can see each other and read facial expressions etc.
I've just done a search and can't find 'concussion' on here...