What can they do now?

[Nevadaref]

Originally Posted by just another ref

He can return inbounds and do anything he could have done had he not gone out in the first place. Dribbling the ball off his own leg would not change this.

Correct. Why people believe that there is something amiss on such a play is baffling to me.

There is absolutely nothing wrong with a player going OOB due to momentum. There is no penalty whatsoever associated with this.