did this person put in his I485 for adjustment of status along side his NIW application? if he did, and he doesn’t have a travel document approved, then he is at risk of abandoning his green card application. That’s my knowledge of this .

He can travel, the Priority date is not near the filling date. He can travel

I think he should only travel if his visa is still valid, if not, I wouldn't advise him to do so because his NIV may not be renewed because they ask if you have ever petitioned USCIS for an immigrant visa

Thanks everyone for the response. He intends to file only NIW for now, but would love to travel by the end of the year.

my lawyers advised NOT to travel while i-140 is pending. reason being your friend will reenter the country on an F1 which is a non intent to immigrate visa. if he files i-140, he has established intent to immigrate and reentering the country on an f1 will violate his visa. they will not let him bk in.

what Chris said.