that is the most humane thing you can do for him now. it is not a hard way to go. I use to work in a vets and had to assist in a few. very easy on the animal. I am very sorry you are having to go thru this. if you want to be with him most will allow that but if you think you can't do it then don't. it is much harder on the pet owner than the pet. my thoughts are with you