A few years back we put down our 17 year old Irish Setter, Boots.
She had two loves, running, and hanging out with us. In her later years, she didn't run much.
She was mostly blind, couldn't hear, and movement was clearly painful.
When it came time to do the deed, my wife, my daughter, and myself accompanied her to the vet.
I held her head in my lap as she slipped away. It was hard as hell, but she left happy, surrounded by those she loved, and she was at peace.
My best to you, and Godspeed to Dali.