Waivers are granted/denied by the individual SA, not by DODMERB. Typically, USNA does not consider waivers until Admissions decides that an appointment offer is likely -- the reason is resources (i.e., no need to spend time/energy on a waiver determination if the candidate isn't going to be offered an appointment).
Based on what BGOs have been told, asthma after age 13, even if controlled by medication, is very unlikely to be waived by USNA. If you believe the diagnosis is incorrect, and can prove that you do not have "adult" asthma, your chances obviously improve greatly.
Can't speak to history of concussion other than to say that each person's medical situation differs, so what happened to others is not relevant to your situation.
I would start with DODMERB -- is there additional information that might influence their determination.