Your friend would be wise to go to court on the hearing date, present a copy of his bankruptcy filing and a copy of whatever notice was sent to the plaintiff's attorney, and make an oral motion for dismissal.
Otherwise, he risks a default judgment that he will have to address later.
There's a good reason for the old saying "An ounce of prevention is worth a pound of cure."
Sure, it's wrong to violate the automatic stay, but it's easier to prevent a mess than clean it up after wards.

