Thank you everyone for your responses. Some more information:
He's 28 years old, single with no children (but eventually those can change so I'm not sure how that affects a service dog).He currently lives in O'Fallon, IL - that is 12 miles from downtown St. Louis, MO - we are considered metro St. Louis area.
He lost his right leg, above the knee, in Iraq in 2007. He still has his hip area in tacked but the end result from the attack and subsequent surgeries is a high amputation leaving him with about 10 inches of leg from his hip.
As far as I know he does not suffer from PTSD and luckily we are close so he has opened up to me alot (which really does help to just talk). He has issues controlling his body temperature due to the attack and subsequent explosion.
He does suffer from some asthma but its rare (his lungs were burnt during the explosion) - and not related to the Iraq deployment he's allergic to seafood (which is a bit humorous as we grew up as a military family deployed to stations near the ocean - so we grew up with eating tons of seafood - he developed the allergy after we moved to the midwest)
He is still active duty but has a desk job - he commutes to and from work at Scott AFB - IL. He does bike ride in a modified bike (one where you use your arms to peddle). He also uses a segway to get to and from his car at work to his office.
His biggest need is an animal to help with tasks around the house and at work which require him to get up/down to acquire items as well as maybe an animal that can assist with mobility/stability.
He uses a wheelchair or crutches when he is not working as his prosthetic leg is very cumbersome due to how high his amputation resides. He can walk with his prosthetic leg with a cane and an "awkward" limp - he's not as sturdy when he wears his leg. His leg is "electronic" and feels when he moves to help with the bending but he has fallen with it as its not 100%.
He's pretty adamant about getting a German Shepard - I know it's better to be paired with a service dog that has been trained and as someone indicated German Shepherds are better at one owner dogs. Through everything he has been through (and of course being my younger brother a stubborn devil) I don't think he will change his mind no matter how much better another path would be.
He doesn't mind paying outright to acquire a German Shepard puppy - but then I wonder if there are organizations that would help to train the dog to be a service dog that meets his needs - in his home or locally he could take the dog to.
He travels with our family sometimes and with my children (10 and 6) we help him out but we aren't always with him to assist. Luckily he was able to go with us on our
DCL to Alaska back in 2011 (he was still at Walter Reed at that time) and it absolutely made his year. We even did a little bit of hiking with him (although he fell a few times).
At this time, when he is not working, his preference for quick get in/out shopping, visiting, movies, etc. is to just use his crutches (no leg) - when he only uses his crutches his hands aren't really free for the everyday tasks. For example, when he comes over to our house and has items he needs to bring in he will calls us before he gets here and we help to bring them inside.
Again I really appreciate every ones responses.