I am not sure what you mean by the accusations were proven. If the priest was already dead, any accuser would have to bring a case against the responsible diocese and prove their allegations were more likely than not.
It might be possible that the allegations were made somewhere near the time of the alleged actions and that the diocese had physical evidence (i.e. records) of the allegations.
If there were no records or other evidence put forward from near the time of the alleged actions, it is more difficult for the claimant to prove their case.
Not impossible, but certainly more difficult.
It is entirely possible that the diocese has had enough claims and the claimant gave enough details that the diocese chose to settle the case (thus people could claim the case was “proved”); however, what would actually happen in that circumstance is that the diocese would settle the claim without admitting liability. That could occur because the diocese had already had enough cases that its insurance would no longer cove damages; and in that circumstance the diocese may not have sufficient funds to be able to defend a long, costly lawsuit.
Not knowing exactly what happened, there are any possible number of scenarios in which a diocese would choose to settle rather than try the case.
Other possibilities are that the claimants had enough information (time, place, nature of the occurrence, etc,) that without information from the alleged abuser, the risk of trying the case was too high; or that the case during discovery noted enough weakness in the claimants’ testimony that it offered to settle to avoid risk of trial, even though the diocese may not have considered the case that solid.
I have seen worse cases in terms of actual evidence get settled for a combination of the above.
Did he or didn’t he abuse? It is entirely possible we will never know. I understand your shock and concern. The best I can say is to let go, and let God.
St. Paul tells us we are all sinners. We hold priests up to a very high standard, and some do not meet that; and some don’t even come close. The Church. in spite of the gravity of the sin, still offers reconciliation" it is the State which offers the pound of flesh.