11yo rottweiler collapsed and now bleeding from the ?

Sounds like it could have been a combination of things - the main thing being that I think he had a stroke - maybe a TIA (mini-stroke) as you said he is doing better. The bleeding i am concerned about as well, although not as much as I think he had a stroke. The bleeding could be crystals in his urine, but it could also be Prostate Cancer and his collapsing could be from that if it wasn't a stroke issue. He does need to see a vet as soon as you can get him there.