Here is a somewhat heart warming and disturbing article in Slate.com entitled " She was 82. He was 95. They had dementia. They fell in love. And then they started having sex." It is nicely written by Melinda Henneberger.
My opinion - the son was wrong in not allowing his father to remain in the facility and the relationship to continue. There are many relationships in nursing homes and even if the couples are in their own realities and not those of this world it is real to them so they should enjoy their life as they have been forced to live it because of dementia or worse. Justice O'Connor bravely has seen a bizarre twist in her life when her husband with Alzheimer's struck up a relationship with someone in the home where he was living, not realizing he was married or recognizing his wife. Her reaction was that this was good for him. Should we all be like that.
The problem in this case was the SEX. And mostly because the son witnessed it. This is a talk that we baby boomers might want to have with our kids. What of this happens and what should you do or not do... Perhaps it is stipulated in a medical power of attorney or another document.
People should be allowed to live their final days in happiness however they define it.