I suppose it’s possible the ruling could go 75/25 where the guy sort of wins and the co-workers win..
I can't think of a situation where that would be that case. The jury will determine from a preponderance of the evidence whether the ticket was part of the office pool tickets. They won't have the option of deciding some kind of split - but the plaintiff and defendants could settle on a split.
Settlements often happen just before the case goes to the jury.