Question Following Medical Waiver for NROTC

[kayaker]

DS was DQ'ed by DoDMERB but received a waiver from USNA and NROTC. Hooray!! My question is, will the DQ and waiver necessarily limit his career path within the Navy or does it depend, and if it depends, how will he know? I understand there are "restricted line" and "unrestricted line" statuses, but I'm not sure how one ends up with those statuses or what they mean. Also, are there degrees of "restricted?" For example, if the DQ pertains to a history of a back injury, will he necessarily/automatically be restricted from flying?