OP=Original Poster

You need to be prepared that this might be a very long process. You might need to consider moving in with family if you don't have another source of income.

No, it does not appear your PN will qualify you with a Listed Impairment at this time. Becoming a klutz does not rise to the level of severity needed. The same thing with having body twitches a few times a day.

Your current Neuro is increasing your meds to hopefully reduce your symptoms and give you the highest degree of function possible, that's not necessarily inconsistent with him thinking you may be capable of working.
The skin biopsy proves you have PN, not what your functional limitations are. This might be a good time to request a referral for a Functional Capacity Evaluation. It will help provide your Neuro with objective test results regarding your abilities and limitations, as well as providing SS with the same. --And he is right, if he just guesses what he believes are your functional abilities, SS may or may not give it any weight. (Those forms your attorney asked your docs to fill out, and that were maybe even customized specifically for you, were probably a version of an RFC form.)

Did you give the Neuro a copy of the form that you had already filled in? If so, that was not a good idea IMO.

BTW, it is possible SS will determine you are no longer capable of teaching PE due to your PN, and perhaps not teach any subject due to your BP disorder, but they might claim you are capable of a less stressful desk job.

In all my lengthy postings to you, the one thing I've forgotten to say is that qualifying for SSI/SSDI is a complex medical/legal evaluation.

One last thing, your brother can write a letter on your behalf, but unless he's a treating source, it will be the same as a letter from any other family member. His medical opinions might be 100% accurate, but they won't help you prove your SSDI claim, which needs medical documentation.