What is the ruling on a daughter giving her father an enema, and what should be done given the situation presented in the question?

It is permissible for you to assist your disabled father with istinja' (washing after defecation or urination) and other needs if he requires it and his wife is not present, and you will be rewarded for that. Scholars have assimilated this situation to the ruling concerning a doctor, who is permitted to look at and touch (a patient) to the extent of the need. You are not obliged to inform anyone of what occurred.