Becky, I'm praying for you and Dakota. Don't give up hope. My Ivy, age 10, was diagnosed this spring with bladder cancer. She will go outside and squat and squat and squat for ages. My vet, who ultrasounded her several months ago said at that point the tumor was taking up a quarter of her bladder. She is on two kinds of chemo medication, which are liquids I give her daily. The prognosis for bladder cancer is not good, and life expectancy is a matter of months. However, Ivy is doing remarkably well on her medication with no side effects. She hardly ever wets in the house now, eats and plays with our other Shelties just like she always has. In fact, she usually instigates the play!
It really is true that dogs don't know they are sick. I hope the same is true of Dakota. If he can be treated and isn't in pain, he could do just fine. Hang in there, and keep us posted. We'll be thinking about you. Hugs!