Well the worst has happened, and I feel like I jinxed Reiner by posting this comment and picture.
Came home from softball tonight and took the dogs out in the backyard. Everyone came in the house after and was fine, and Reiner went to his bed and went to sleep. About an hour later his head popped up like he was startled and he tried to stand up, but was staggering and nearly collapsed.
By the time I got him to the emergency vet his gums and ears were almost completely white and he was nearly passed out. Long story short, they did an ultrasound and he had a softball-sized tumor on his spleen that was bleeding out into his abdominal cavity. His blood pressure had dropped to the point of him staggering about and passing out. They stabilized him but the only options were to do immediate surgery with a very low chance of success. (and "success" meaning we would buy him limited extra time. i.e. about 3-6 months.) or to go ahead and let him go.
RDToy is out of town, so I made some calls and we decided to let him go and not make him suffer just to buy us some extra time with him. Managed to get RDToy and her dad on video chat in the room with Reiner so they could at least see him and say good bye. I held it together pretty well until it was over and I was alone in the room with him and RDToy had gotten off the phone to give me some time to say good bye by myself. Then I pretty much lost it.
He was a damn good boy and the best friend I could ever ask for. I loved that dog and am proud to have called him mine for the past 9 plus years.