If what your friend did was an online impersonation of someone, and harm to the one impersonated resulted from your friend’s action, a civil action, a criminal action, or both potentially could have been pursued.
And it could be possible even now for a legal action to result over older online content or internet activity - if recently discovered by the one who was impersonated. A defamation claim, for one example, potentially could be pursued under a state’s “discovery rule.”
Specifics really should be discussed with a New York attorney, if your friend is concerned.