The kid is 19 and he's immature and doesn't know or understand how good he has it (being paid VERY well to play a sport he loves). He doesn't understand how real life works and doesn't understand how most of the world wake up everyday going to a job they hate.
He shouldn't be making these stupid errors of judgement but at 19, we think we know it all and are above the law and everything else. Does that excuse his behaviour? Not at all. What should his punishment be for this latest indiscretion? Well, it depends how you look at it. Was it a serious offense? Not really but it could of turned serious had he hurt or killed someone whilst looking at his phone while driving etc.
What to do? I really don't know but what I do know is, if he worked any other job and done this, his job wouldn't sack him or suspend him, he'd still have to turn up everyday and do his job. His job probably wouldn't know about it tbh. Look, it was a really stupid thing to do. I say, fine him again but don't suspend him from more games and get him to speak to a sports psychologist or someone that can guide him and perhaps make him see the error of his ways and hope he'll learn from all this.