So we still don't know the truth.
"Adjudicated mentally defective" and "committed to a mental institution" are both terms that appear in question 11.f of the 4473. If we then turn to the instructions for question 11.f we find the following:
Question 11.f. Adjudicated as a Mental Defective: A determination by a court, board, commission, or other lawful authority that a person, as a result of marked
subnormal intelligence, or mental illness, incompetency, condition, or disease: (1) is a danger to himself or to others; or (2) lacks the mental capacity to contract or manage his own affairs. This term shall include: (1) a finding of insanity by a court in a criminal case; and (2) those persons found incompetent to stand trial or found not guilty by reason of lack of mental responsibility.
Committed to a Mental Institution: A formal commitment of a person to a mental
institution by a court, board, commission, or other lawful authority. The term includes a commitment to a mental institution involuntarily. The term includes commitment for mental defectiveness or mental illness. It also includes commitments for other reasons, such as for drug use. The term does not include a person in a mental institution for observation or a voluntary admission to a mental institution.
[Note: Blue added for emphasis]
So "adjudicated" has a clear meaning under the law, but that doesn't mean reporters, or the people talking to the reporters, understand it. Remember, both the Social Security Administration and the Veterans Administration were reporting people to NICS as "mentally defective" solely on the grounds that they had trouble managing their finances and had designated someone else to receive their benefits checks. In both cases, the agencies claimed that their administrative actions constituted "adjudication." IIRC, courts disagreed.
People can be confined to a mental institution for a short stay (around here I believe it's three days) for observation if it is believed that they
might be a danger to themselves or to others. Even though such confinements are ordered by a judge, the instructions on the 4473 are clear that such "temporary" confinements do not constitute being adjudicated mentally defective, and thus do not prohibit the person from buying or possessing firearms.
So ... was this guy actually
involuntarily committed or adjudicated mentally defective, or was he admitted for observation and then cut loose without being either
involuntarily committed or adjudicated mentally defective? Somebody must know the answer to this but, at the moment, it seems to me that "they" are trying very assiduously to NOT tell us.