I don't know how your friend's ride but for my experience, I had it happened to me twice already.
The first time, I was kind of scared and asked tons of questions. Then I decided, what the heck, I will simply plug it. I was also told to only used motorcycle plug and should only be done from the inside.
Well, I had done many plugs on car tire before and I know they stick very well. So I plugged my first nail with a car tire plug right from the outside. This nail was right in the center of the rear tire. I since put over 2K miles on that rear tire until it was almost down to the thread. I road with that tire with speed up to 110mph on the freeway before I replaced the tire.
Two weeks ago, I got another nail in my brand new tire. This time it is 1.5" to the side from the center. I just plugged that son of a bitch again and pumped the tire back up. Thirty minutes later, I was riding on that tire again. I am still riding on it right now and plan to ride on it until it wear out.
Am I concern? Yes. I know that I am not riding on a perfect tire so I alway check up on it. Other than that, I feel pretty comfortable about it.
But if your friend's is into stunting, then he may not want to patch it.