Sorry, I have only just seen this. My rescue springer Heidi had liver failure at 9 years. We treated her for several weeks. The day she stopped eating and was sick(same as Max) was the day that I took her to be pts too. You made the right decision. Better a day too soon than a day too late.
Run free at the bridge Max
. No more pain and a puppy again.
(((Hugs))) to you and your family.