Hello and Welcome to ‘Ask A Doctor’ service.
I have reviewed your query and here are my thoughts.
Noted the history about your brother's accident,
MRI findings and status of pain and weakness.
I would advise him the following in such a situation:
Neurologist's opinion, but there is a long wait.
Take him to Er and ask for
lumbar puncture for sending the spinal fluid to the lab for analysis as it may then give a clue as to why the problems persist in spite of only lower lumbar problem on MRI.
This may also indicate the cause for the pain in the back radiating to the chest. Another possibility is of
nerve root compression that may not be evident on MRI.
Take him to the Physiotherapist for proper training.Give Multivitamins and mineral supplements so that healing is faster. Nervous system takes the maximum time for recovery.
Hope I have answered your query.
Let me know if I can assist you further.