Peaceful thoughts I would imagine just before the end all the nerves firing at once and a rush of memories and images flooding past. Than at once it all stops no more signals consciousness fades to nothing the heart stops and breathing ceases muscles go limp.

Seen too much death already but that's about the way it goes.

Anyone's guess as to what happens "after" but it sounds like its between something else, or nothingness.

May as well enjoy life while you can before the inevitable.