Brother, thank you for sharing such a touching story. It reminded me of the following hadith:Just a thought. My first wife was a very devout Christian throughout her life. She had very little knowledge of Islam. I was definitely an agnostic trying to live as a Buddhist at the time of her final days. Yet, for some reason within minutes before she died she gained consciousness, smiled and said the Shahadah.Those were her last words. I was not with her when she died but that was related to me later by the doctor who was in attendance with her. At that time neither the Doctor nor myself were Muslim and we could not understand the significance of why she would say the Shahadah. The Doctor was a family friend who was a Roman Catholic Arab from Lebanon and fluent in Arabic.
Abu-Dawood 2203 Narrated Umar ibn al-Khattab
Muslim ibn Yasar al-Juhani said: When Umar ibn al-Khattab was asked about the verse "When your Lord took their offspring from the backs of the children of Adam" - al-Qa'nabi recited the verse--he said: I heard the Apostle of Allah (peace be upon him) say when he was questioned about it: Allah created Adam, then passed His right hand over his back, and brought forth from it his offspring, saying: I have these for Paradise and these will do the deeds of those who go to Paradise. He then passed His hand over his back and brought forth from it his offspring, saying: I have created these for Hell, and they will do the deeds of those who go to Hell. A man asked: What is the good of doing anything, Apostle of Allah? The Apostle of Allah (peace be upon him) said: When Allah creates a servant for Paradise, He employs him in doing the deeds of those who will go to Paradise, so that his final action before death is one of the deeds of those who go to Paradise, for which He will bring him into Paradise. But when He creates a servant for Hell, He employs him in doing the deeds of those who will go to Hell, so that his final action before death is one of the deeds of those who go to Hell, for which He will bring him into Hell.
How are we to know our own hearts to judge that we know we are saved, when we don't know the final act before we die? As you demonstrated the example of your 1st wife, so also the flip side must be true that one can have the outward appearance of being a devout Muslim yet his final words be of shirk.
Note: Christians, the fundamental Islamic belief of Al-Qadr is difficult to grasp. Allah has created us as He has willed to do so and who are we to question why. Since we don't know what our destiny is, we must live our lives with the fear of punishment and the hope of Paradise. This gets back to my prayer - to die not but as a Muslim.