As to whether you should disown, that's a personal decision. Remember that doing so could create huge problems for your other heirs. Do you really want to put them through some protracted litigation? I've seen these lawsuits. They drag on for years and the results are never pretty.
A friend of my wife divorced her husband. He is a cheating scumbag, but crafty with money and lawyers. Over several years, she has burned through more than a half million dollars in legal fees and the divorce STILL isn’t final. Not pretty, indeed. You want things rock solid and tidy after you are gone.