You are being dramatic. No one thinks he should disown her. Just not condone her lifestyle.
I think it’s the left that is being dramatic, in constantly trying to paint Republicans as a Christian version of the Taliban. When the Cheneys lovingly embrace their daughter, or the Bush twins travel to third world countries to work with impoverished people (while Chelsea has a cushy six digit job on Wall Street) it messes with their view of Republicans as the secular devil.