I’m so sorry you’re going through this. As someone who recently said goodbye to my heart horse, I’ll try to add some perspective.
Based on what you’ve shared, it sounds like it is his time. My gelding was 30, had arthritis for many years that was previously managed well with Equioxx. After 5+ years of Equioxx he started to have recurring colic episodes, mild but increasing in severity and frequency. My vet suspected ulcers, but also could have been strangulating lipomas - no way to know for sure.
My boy couldn’t tolerate the amount of meds needed to keep him comfortable, and the thought of losing him to a painful colic haunted me. I decided to give him the peaceful and dignified end he deserved, rather than an emergency or painful departure. He was still eating, getting around fairly well, but the spark from his eyes and personality was just gone.
One thing my vet told me was that none of her clients have ever felt it was too soon afterwards. It always feels that way beforehand though. My horse had a wonderful last week. We spoiled him, some old friends came to say goodbye, and we celebrated his life, laughed and cried together.
When the day finally came, I was a wreck, but when he went as peacefully as any horse I’ve ever seen, I knew it was the right call. He was ready, even if I wasn’t. I won’t lie, I still miss him every day and probably always will. But I have peace with my decision, knowing it was the right thing to do for him.
Wishing you luck with this tough decision and peace with whatever you decide.