I had to put my jack russell down a couple months ago, he had succumb to dementia. He was just shy of a solid 17, my parents got him for me when I was 12 so we grew up together, liitle dude was awesome and will be forever missed.
I agree with @Ruff, no need to make a shit situation worse by having to do it yourself. I'm lucky enough to have a family friend who is a vet, she came to the house and gave him a tranquilizer first so he just drifted off on his couch. (he claimed a couch, he was a spoilt dog)
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