I’m 44. Not note whatsoever.
I’d pay it. Can you use the 401k as a loan ?
Interest on a 401k loan is about 2% over prime , so floats about 8-10 % . Granted he'd pay himself , but it's still double his 3.6 rate. In my mind not a good move. If he needed a small amount for a short time , a 401k loan could be an option. He'd also be missing gains on that 401k $ at possibly more than his payback rate.