I am so sorry to hear your dog is not well.....
I know what you're going through, my 13-year old mutt has developed heart problems recently, which gives her trouble breathing.
She's taking lots of medication, which helps a little, but not much.
It's horrible when it goes downhill so fast!
Anyway, a spread:
The first thing that came to mind for me is a very simple four-card spread.
1: How do I feel about the situation
2: How does my dog feel about the situation
3: What I can do to make myself feel better
4: What I can do to make my dog feel better
Mmm. Not completely happy with it, writing this.
Maybe add a fifth card, sort of a lesson/guidance card?