Well, this is interesting.
There is generally a three-year statute of limitations on copyright violation claims, and it has been more than three years since the film was released. Unless he was hiding under a rock, I don't know how he could claim he didn't have knowledge of the song for more than a year.
Music copyright cases are hecka interesting though, and can involve music mapping (pretty cool graphic designs) for the jury to try to see similarities and not just hear them.
Personally, I don't hear enough similarities, and just writing out a bit didn't see enough on paper either. But I'm not a music expert, so who knows. It is quite possible that Disney would calculate the costs of a trial and music experts, and then settle for that amount simply because it is more efficient. (For that reason, don't be too shocked when you hear things settle out of court: many cases do settle simply because--even if the defense has a really, REALLY strong case--it is costly to go to trial, so they may settle an action just to try to save some of that cost, without admitting liability).