When the time came for my Dad - I was less than useless when it came to letting go. And similar for the dog several years later. Although that was more my Mum and sister's fault. Should have been done before Christmas that year, and Mum phones me a week or so after Christmas - on my birthday - I referred her to my brother for help and he did. I couldn't help PTS the dog on my birthday.
Maybe another member of the family could help with the decisions. If Russel goes quicker - right now - is that a good thing or a bad thing? For my Dad - it would have been a good thing. And I know it's going to rip you up inside but is that enough reason to delay? Again - someone a little further away from the centre of it all might be able to help see things more clearly - and I'm not thinking of us on forum.