she knows Leo's history.
and yes, pancreatitis can treatable, he might not have another bout with it, either.
others here have said it, and it really is true, when he's ready to go, you WILL know it. I didn't think that was possible, but my 4 year old cat let me know it was time. I never in a million years would have ever thought a 4 year old cat could NOT be fixed.....and I could have tried a couple other treatments, but when I looked into his eyes that morning, he was telling me he was done.
You will have that certainty as well, when it's time.
It's hard dealing with a sick pet, so please be sure to be gentle with yourself, as well.
