I'm not saying that attention shouldn't be given- but there are many dogs that have so much energy especially with puppies- that there's no feasible way to expend it all by playing with them. This is where tools like a treadmill are useful. Also using backpacks on dogs when they're on walks and giving them little jobs to do.
There are just many dogs (often in working breeds) that have more energy than most people can handle. When you take these dogs away from the jobs they were bred for and try to make them house pets- some get bored quickly and start acting out. A great example is a pet husky in Las Vegas. A dog bred to pulls sleds for miles and miles in snowy cold weather- kept indoors (because they have to be) as a house pet. It takes creativity and ingenuity to come up for solutions for that. Now should a husky be owned in that situation? That's a question that I have an opinion on which I'm sure doesn't agree with everyone else's in the world.
Basically- high energy working dogs need a few things above the basics of food, water, shelter and love. They need to expend their energy, they need to be mentally challenged, and often they need a job. (Which can be taking a toy to the door when someone rings the doorbell, carrying something in their backpack (like bottles of water), pulling around a kid's wagon, catching rodents, or anything else you can think of). It depends on each individual situation what will work best. Since the OP mentioned having mobility issues I suggested something that would require less major movements for them. Training a dog to walk on a treadmill is pretty easy, and mine enjoy it. I often play with toys and treats with them on the treadmill. The key is making it fun! Another great thing is swimming, but a pool is often a much larger investment and I find more dogs hate swimming than walking.
I suspect this "gifted child" of a dog needs a major combination of the above but it may end up looking very different than any of us are picturing it. It's hard to give a concrete solution without seeing the exact situation the pup is in and seeing the exact actions/reactions of the pup /owner.