<human>: When I was 4, my parents brought a puppy into our family. He was an Australian Shepard-Mix, and he was fucking awesome. When I was younger and didn't have many friends, he was always there for me to hang out and play with and as I grew older he was still there for me. I have no way to describe the bond between a man and his dog, but I truly understand where the saying "man's best friend" comes from now. 

Fast forward 15 years and things have taken a toll for the worse (obviously). He's had a problem with his hips for about 3-4 years which required him to take aspirin, but apart from the occasional slip-up (read: legs giving out on him) he did fine. I noticed he was getting around more gingerly about last year, but he still seemed happy, had an appetite, etc. but he still only had the occasional accident. Two days ago I woke up in the morning to find that he had pissed himself at night and was unable to get up out of his dog bed. I picked him up, washed him, and kept an eye on him for the rest of the day. All was well, but he seemed really weak. Today the same thing happened, except even after I had picked him up and cleaned him he wasn't able to do anything. He could stand for a bit, only to succumb and lie down. He seems miserable, but I don't know if I can't justify putting him down. I don't want to betray his trust, I don't want to be the last thing he sees before he's put down--I don't want him to realize that I've killed him. At the same time I want to be there for him, like a good owner should. It should be mentioned that I still live at home and this is a family issue, it seems that my parents are leaning towards putting him down. How am I supposed to cope with the loss of my longest companion? Am I justified in putting him to sleep? I've never dealt with true loss in my life so far, so this is all uncharted territory for me.

Can you provide a brief overview of the text?
<bot>: My dog, friend, and companion will probably be put down very soon. How am I supposed to handle this situation?