I'm so very sorry for your loss. I haven't read all the responses. I just couldn't.
My heart hound, Faye Oops, was the first dog we had PTS (osteo). Faye Oops always got very stressed at the vet's office, so we always brought Celeste with us to appointments. We did the same when it was her time to leave us. The sedative did nothing. Faye Oops was still stressed. Thankfully, Celeste was there and put her head on Faye Oops to calm her. It worked. I will be forever grateful for Celeste that day. She even had the staff crying.
We recently had to PTS my heart cat, Monty. He was the first animal that I've had to have the reflexes after it was done. It was very unsettling.