Sorry for your loss. My mom passed at the young age of 93 from Alzheimers. You are right that it was a blessing for your mom to be spared the much longer road of suffering Alzheimers can take you down.They gave her both antivirals and antibiotics. Where you are 87 your immune system is far weaker than when you were 47. She was basically dead 10 days before she was clinically died. They found her somnolent one morning, 0200 hrs, in the Memory Care unit that she live in and called 911 and us immediately. The virus ravaged her nervous system and brain rapidly and irreparably.
In the long run, it was actually a blessing for her. The Alzheimers had progressed to the point that some of the physical degradations were just beginning to manifest themselves. It saved her from the much longer slow death of complications due to Alzheimers.