To Tell the Truth, or Not to Tell the Truth. That is the Question...

Telling the truth should not be considered a moral dilemma. According to Kantian ethics one should always tell the truth because it is morally right. But what if telling the truth would cause great harm (psychologically, emotionally, or physically) to the opposing party involved. For example, let's say that there is a family that is caring for their elderly grandmother who has recently developed Alzheimer's. Eventually, the grandmother forgets who each member of the family is, but still believes that her deceased husband is still alive and has asked to see him. Should you lie to her or say that the husband is away on business? One would think it would be a more humane solution to simply tell the woman that her husband is not there at the moment, as opposed to putting her through the heartbreak of telling her again that her husband is deceased. What's the harm? She won't remember anyway. But if one has to make exceptions to the moral rule of always telling the truth no matter what, this is not a viable option. So we are led to the rules of utilitarianism. It would cause less emotional and psychological harm to the grandmother and the family if they played along with the fact that the grandfather is still alive, but he is not there at the moment. It would cause more harm to break the heart of the ill grandmother and to (most likely) repeatedly tell her that her husband is gone. But is it okay to lie to patients for their own sake? Should they be forced to handle the truth and deal with reality because it is a part of life? Or is it more humane to let them live in ignorant bliss until their time has come?