I’ve been searching for any reported cases with the same/similar allegations as those depicted in the OP for a Trust wallet notification, coming back empty handed. I’m inclined to believing that, as others have mentioned, the notification was not the root of the issue, but rather either accesses a phishing site or a fake app with malware.

Depending on what phone your friend is using, and the OS version, he may be able to retrieve the notification history (not all phones allow this, but some do). I really doubt this has anything to do with it, but it you’re capable of accessing the history log you may be able to see something or other.