Back from hospital (for now). Grandpa still in a coma, so myself and my parents are going to take turns watching over him throughout the night. My turn is 11 PM - 3 AM, meaning I have some time to relax and take care of Se7en business now.
It's not that "simple", since a patient can remain in a comatose state for a while and doctors usually give a time period in which they believe the patient may die. The most probable scenario is that he dies in his sleep, but still your reasoning is not false.
