French husband need a return plane ticket?

So I got a great deal on a plane ticket but it was only one way. My husband is French coming to visit me again at the end of August.  Will he have problems from Border Patrol if he doesn't have his return ticket?
He has only an esta and knows he can only stay 90 days. He has his children in France and work he has to get back too....is that a good proof he will return?
We plan to move my kids and I to France next summer.
Thank u!

Hello.
In which country are you?

Im in California-USA

It used to be that you HAD to have a round trip ticket, check with the airline. It is pretty stupid, I know, since if you want to stay, you just don't use the return ticket......

So we do??

Ask the airline since they are the ones who check if you have the round trip ticket at check-in.