Hi and welcome,
Your dog's injury sounds like it is in the same place where my dog was injured, around T12-13. You are right, your dog can have a great quality of life and he will continue to be the same personality you have always loved. During the first few weeks after your dog comes home, you are doing a lot of brainstorming and trying different things to get everything arranged and learn a new routine with your dog. It can add up to quite a bit of stress while you figure it all out, but the good news is that dogs do survive our learning curve. You can probably expect that people around you to be pretty clueless about what you are going through, they have no experience with it. But once you get your routine down, it just becomes a new normal.
It sounds like probably your dog is going to be incontinent. When a dog has a spinal injury in the area you describe, they tend to hold their urine and are not able to urinate even if they can feel they need to. Your vet should show you how to express his bladder. That means you squeeze his tummy in a certain way to make him pee. When a dog has a spinal injury near the tail, the urinary sphincter is loose and the dog is usually easy to express. When the dog has an injury up where your dog does, the sphincter tends to be tight and it is harder to get the dog to release urine. You may want to ask the vet about medication for an "upper motor neuron bladder" to relax his sphincter, at least for now while he is newly injured and you are learning to express. However the advantage is that dogs with an injury in this location tend not to be dribblers or leakers unless the bladder is extremely full and overflows. This does not happen if you express the bladder every 8 hours. So while a male dog with a spinal injury closer to the tail might need a male doggy diaper to keep his bedding dry, your dog may not need one. If your dog does need a diaper, be glad he's a boy because malewraps are your friend. They are a wide belt that goes around the waist and fastens with velcro, and they hold an absorbent pad over the male area. I had a dog who wore male wraps (aka belly bands) 24/7 for 2 or 3 years. You can do that if you apply ointment to protect the skin from diaper rash.
Here is a link to an article with a lot of videos at the end, showing different ways of expressing. (For some reason the pictures are not showing in the article, but the videos are at the bottom if you scroll all the way down.)viewtopic.php?f=5&t=16027
I assume you will want to handle him as little as possible while you are waiting for his fracture to heal. Did the vet say anything about surgery to stabilize the fracture? A board certified surgeon knows how to realign the break and knit it together with pins and bone cement. In time the dog's own bone will grow into the break.
My dog actually learned to walk again after a lot of PT.
You can see her x-rays here: http://www.fourfurfeet.com