So I'm slated to babysit a wounded dog. What do I need to know?

[Imago]

He's an 11-year-old black lab with a severed anterior cruciate ligament. Due to a heart condition, they can't repair it with surgery. The owner is looking at a splint but right now everything's unsure. There'll be four weeks of recovery before he can walk at all, and running is absolutely out.

Technically he belongs to his owner's son, a former classmate of mine from high school, but the old pup is her baby without a doubt. She went so far as to ask me for a reference when I volunteered to sit him and to draw up a schedule. I know her mostly from online communication right now (she's a fan of my writing); one of those Buddhist businesswomen types, outdoorsy, pragmatic, assertive. Which is to say that though we get along quite well now, if anything were to happen to Doggy on my watch I'd expect my head to roll.

Dog and owner live a four hour drive away and she will be gone from June 2nd to the 10th. I'm somewhat experienced with dogsitting but I haven't done it in a while (mostly just during the years when everyone else babysat for pay). She's been pretty open about the fact that this will chain both dog and sitter to the house and front yard, and says he can be left alone for an hour or less at a time. It's quiet up there and a very short walk to a peaceful riverbank; I don't mind being penned in.

Right now the dog is noticeably depressed by the new movement restrictions, but in my experience dogs adapt well to this kind of thing given a bit of time. The stress of being restricted has screwed his digestive system up atm, and he can't have his pain meds until that settles down. He already has arthritis in his hips- the leg injury is going to speed that up a lot, the vet says. In her words, "Calm and relaxing energy is what this babyboy needs".

I volunteered rather quickly on a hunch that 1) it would be hard for her to find any other sitter with equally good intentions, enough spare time and any experience and 2) I'd probably benefit from a week of uncomplicated responsibility and canine company myself. So while I don't quite think I'm in over my head, I definitely want to take every precaution!