Geralt will die alone as there is
No Witcher Ever Died in Their Bed
This is one of the things that makes me reconsider whether Geralt as a character would even want to settle down for a long period of time with Triss (or anyone for that matter), it just doesn't seem like him.
I've unfortunately not read the books yet, so obviously I don't have any grasp of book Geralt as a character :/