OI again, sorry for your loss. My family went througt that with my dad. After and operation and after seeing him. They asked, what if, we said nothing he passed with an hour or so.
Mom, we/they knew it was coming , and they kept her comfortable and passed on with no pain.
I have seen people lay there for years and with no sign of recovery, why? Everyone suffers in this situation.
When my mom was in, Dr Maida , An amazing person told us this is a war we can fight but the outcome will be the same. She was 90+ we let nature take her course and shortly after she passed.
It will happen and why suffer.