I find the concept of a ‘last thought before death’ quite a difficult thing.
Firstly, when is the point of death? I’ve seen quite a few people and animals die and it only seemed really tangible on one occasion, and even then it took at least a full second for it to happen - plenty of time for lots of thoughts to have arisen during that process in my experience. From a sciencey point of view, the point of death has changed a couple of times in my lifetime - first it was stopped breathing, then stopped heart, now it’s brain dead. And brain death has different definitions in different countries.
Secondly, experientially, my thoughts seem to do things like: bubble up, half form, sink away before I can grasp them, then another thought might overlap as it forms. So while there are gaps between fully formed thoughts to some extent, I’m not sure when I would call a thought a thought, and when I would call it something like an embryonic thought.
What I mean is that the processes of both death and thoughts are quite messy, and I’d be surprised if they lined up to always give us a clear ‘last thought before death’. But I might be misunderstanding what is meant.