This is a place to start reading:
There is a process. The good news is, for involuntary separations for medical fitness reasons, there is virtually no possibility of required monetary payback.
Your mid will get briefed, sign papers, be informed of healthcare rights from VA.
I strongly recommend keeping a log of the who/what/when of things he is told along the way, so he is clear and knows what he was told by whom and when. Once he is separated from the Navy as part of DoD, healthcare for the service-related documented issues shifts to the VA.
Keep good paper files, email files, screenshots.
I am sorry to hear this. Looking down the road, if he ever decides to go into federal civil service employment, his USNA years can count toward Federal retirement years (but not military retirement, for other readers).
And - be sure to research your state’s veterans affairs bureau/agency/department for state benefits, which are different from federal benefits. They may define “veteran” in such a way he qualifies. Due to the nature and brevity of his service at USNA, I don’t know what federal VA benefits he is eligible for. There are Veteran Service Advisors (VSO) in states, counties, bigger cities, as well as at local vet organization chapters, who can advise on federal VA and state veteran benefits. The state benefits vary by state. We had a sponsor daughter who developed Type I diabetes and was separated after 2 years. Her home state veterans benefits paid for her to complete her degree at a choice of 3 state universities. The certified veterans benefits counselor at the local American Legion Post back home took good care of her. Membership not required. Free service.
And welcome new member of 35 minutes! Sorry it is under such difficult circumstances.