This is so very sad. Now I understand why you feel so passionately about the subject of SM and encouraging breeders to screen their dogs.
I do wonder how many dogs with SM have gone undiagnosed, or diagnosed as something else. With hindsight I suspect a lot of owners are now wondering if SM was a problem with an earlier pet. I am currently wondering about my mum's dog Fern. She was an ex-breeder's dog we got as a rescue, and has on occassioned cried out when touched around the front legs. It hasn't happened often, but I am now watching her closely and will check with the vet if it happens again. I haven't told my mum as I know it would worry her sick - my parents are in their 80's so I deal with all the vets stuff anyway. We all love these little dogs so much, so I hope more breeders will screen in the future.
Oh I'm so sorry to hear about Nemo's suffering. You were probably right about the SM (from the knowledge I have gleaned from this site) Thank you for sharing his story. It will serve as a prompt to ensure that I do my best for my cav and any future cavs I may be lucky enough to share my life with.