Is it permissible to use olive oil from trees that were irrigated with water of questionable legitimacy in its acquisition?

What the father did is a forbidden transgression that must be ceased. The value of the consumed water should be estimated without paying for it and then paid to the responsible authority or for public welfare. As for the questioner's benefit from the olive fruit or its oil after the trees were irrigated with that water, there is no sin upon him in that.