I don't see it as eating up the thread, you had an important experience to share, and we're supposed to be here as friends and as a community to be that shoulder you can lean on when you're down. Don't feel bad for wanting to talk about what happened, it's good to have dialogues.
I am terribly sorry also to hear about a neighbor drowning. That's dreadful, and I can imagine all the confusion and fear when you found your cat too at this time. Again, I am sorry that your community at home lost someone else.
Something that I think is good is that you were able to give a cat a long and healthy life so that he could have a natural and peaceful conclusion to his story, it doesn't change the pain of losing him, but when so many pets have their lives cut short and may never even get to leave an animal shelter or get to experience kindness from anyone as they live in the street, i'm glad that your cat at least crossed over peacefully on his own terms at a ripe old age in the outdoors, no signs of pain, injury or fear, he just drifted off to sleep where he was comfortable. You really make your cat come alive in my imagination with everything you tell me about him. I understand how you must miss this adorable fella. I have been there too, having burried a pet. Let me give you another hug. /big teddursa bear hug