I'm assuming the dog is seeing a boarded surgeon if they're talking hip replacement surgery, rather than an FHO (femoral head ostectomy). However, there are risks involved in both procedures, and the fact that the dog is less than a year old means that the hip replacements may fail before he's ready to be done using them. He's also got a little growth left, and I'm not sure that doing implants before the dog's done growing is the best thing for the dog. He is almost certainly going to have to have them done one at a time, whether an FHO or hip replacement is decided (so unless then $10K is for one hip, at least you'll only have to come up with $5K at a time).
Have a long conversation with the surgeon about the pros and cons of different options. Potentially talk to other surgeons, if that's a resource available to you. An FHO is likely to be cheaper (though I don't know what people generally charge), and more vets will be able to do it than a total hip replacement.
There is also always the option of no surgery - I don't know how bad this dog's hips are, obviously, and they don't show a shot of the rest of his body, so I can't tell how much muscle atrophy he might have, but some dogs can do fairly well if managed right - kept at a slightly light weight, lots of swimming and walking for exercise, no running or jumping, potentially joint supplements. These are probably all things that would have to be maintained for the rest of his life, whether he had any surgery or not.
Do some research into hip dysplasia and the different options of treating it. Talk to the surgeon about the condition and what they think Harley's chances are for each type of procedure. Talk about potential complications. Talk about that surgeon's success rate. Talk about long term management, regardless of the procedure done. It's not an easy decision to go to surgery in the first place, and even less so when the dog isn't technically yours yet. If the surgeon is pushing one particular treatment and not being willing to talk about the rest of it and why they think one treatment is best, ditch him, and go to someone else.
I'm avoiding going into specifics because I'm not a vet yet, much less a surgeon, and this kind of information is best given by the veterinarian being consulted about a specific patient. I've given you enough info that I'm sure you'll be able to get some more from the internet to help give a groundwork for the conversation that will need to happen with the vet.
It's great that your family is willing to take in a dog that's got this kind of problem knowingly - most people wouldn't even consider it, especially with the price tag on the surgery on top of it. Good luck to you and to Harley
