"or 1099-NEC"

You never get a 1099-NEC from your own entity.

"First he firmed LLC, and then he did S Corporation election"

Someone gave him this guidance, and they should have told him about all the requirements. That includes payroll. LLC is a State entity construct. For purposes of the Feds, he is running a corporation, and the corporation is a separate entity from himself as an individual. Think of it as: The Corporation hired him to do the work, and he is the corporation's employee.

"whatever NOI he has he got K-1, still he has a Problem?"

He needs more guidance than we can give you to give him over the internet. You both would be able to learn from mentoring. We all started somewhere.