Hello USAFPhoenix,
WELCOME to this great forum!
I commend you for wanting to try and help your younger brother. A good BIG brother you are.
With his lower back pain going on now for 6 months and that thingling sensation in his left hand and toe, I would highly recommend that he seek the advice of a neurologist/spinal surgeon without delay. Back pain is one of those things that sometimes is difficult to determine what ones self did "wrong" if anything.
I would suggest that he speak with people he knows who have been to a neurologist or spinal surgeon in your area. Find out which doctor they liked and which ones they did not like. He needs a spinal doctor who is well respected. The best he can find. He may also wish to call the local hospitals and ask them which spinal surgeon performs the most surgeries. (I'm not saying that your brother needs surgery, I'm only saying that you want a very experienced doctor who is best able to determine what is causing your brother's pain. I am NOT a doctor, however, from my personal experience, that thigling sensation is an indication of a pinched nerve which in my case was caused by a bulging disc.
Oh yes, after he has determined who are the best spinal doctors in his area have him make an appointment with one. Then immediately make an appointment with another spinal surgeon on the list, and preferably a third doctor. It is always a good idea to get those second opinions.
I wish your brother well. Do stay in touch and let us know how things go. If he or you have any questions along the way don't hesitate to ask.
RichT
P.S. - If he has a professional sports team in his area I would suggest that he give the team's office a call and find out which spinal doctor or neurologist the team uses for their player. With the investment the owners have in the players they don't want the cheapest doctor, they want the BEST doctor. This approach sure has worked for me.