It's a he said/she said case. If I had to pick a side, I'd say he is more believable than she is. But I am not sure I'd be convinced enough to find in judgement against her if I were on the jury.
I guess the reason I kinda lean towards his side of the story is that she left the scene. I do kinda fault Paltrow for leaving. He did break four ribs and had a concussion, which nobody disputes. You don't leave an accident if that happens. If I'm involved in an accident and the other party appears injured in any way, even if I am in no way to blame, I am not leaving until ski patrol is there and I have told them what I think happened. Actually, especially if I am not to blame I would stick around. I'd want to avoid just such an outcome where the other party talks a big story about how I whacked them out of nowhere and then skied off. If I'm not there, then at least one part of that story checks out and appears credible.
Edit:
I'll go ahead and note that he is not exactly a sympathetic plaintiff, and there are plenty of valid reasons to question his motivations, in part due to some of his own actions afterwards. So yeah, I think if I am a juror I just want a week of my life back and to be allowed to go home.