Missing the cutoff for BasicMed by 11mo is really hard to sell as "oh, that was an innocent mistake". Would be interesting to understand the reason they went for this approach instead of getting another class 3 medical one more time, since it seems your friend already had one previously. I can think of a few scenarios, but none that are going to make the FAA happy about the situation.
Regardless of reason, though, every flight your friend took as PIC after Aug 2005 that required a medical (BasicMed or higher) was factually illegal. Depending on where your friend flew, how often they flew, if they had regular passengers, I could see the FAA being particularly unamused. Not sure if will be something like "Your 586hrs are now 87hrs (whatever you had in Aug '05)" or "Your certificates are now trash. You can try again after a (defined) delay."
Another consideration would be the insurance company. While the basicMed itself (probably) didn't cause this accident, now that they know that your friend has been flying w/o a valid medical, I think they may have some concerns they will want to discuss w/ them about the situation. I could also see insurance (whether your friend's, FBO, friend of a friend, etc) refusing to pay for this mishap since the pilot was not legal to be PIC.
Considering the response the FAA has had to some high profile pilots in the recent past, I doubt this will be a "You're forgiven. Go forth and sin no more." situation for your friend.