If he hasn't done it then nothing less than a full explanation of what was said will do. He should rightly face no further action if he hasn't said anything of a racist nature.
If he HAS said something racist then a hefty fine, racial awareness course and massive ban will be coming his way. For their club captain to allegedly do this would be enormously damaging to the club and the brand. Let's not forget that Liverpool, like all clubs, have a multiracial dressing room. How will his teammates look at him? This could shatter team spirit and be the beginning of the end for Klopp when taken with their poor form. In their own minds, they were able to wash over Suarez-Evra but times have changed even since 2011. In the end, Suarez was just put down by the media as being ignorant and stuff that was acceptable in South America was not acceptable here. Henderson has no such excuse. He has nowhere to hide. He's put himself at front and centre of the anti-racism campaign. IF he has done it, his career is done and that club plunges into further turmoil.