I'm very sorry to hear about Tok, he was a beautiful dog.

I've never heard of Degenerative Myelopathy before but I did some research on it and it sounds terrible.

As for bloat I did have a dog die from it about 5 years ago. At that time I had no idea what bloat even was. By the time I could get our Keisha to the vet she was just about gone. She died on the table.
It's something VERY, VERY horrible to watch and I'm sorry you had to see your poor boy go through it.

My condolences to you.