I kind of scanned the answers here.
I had thought I have nothing to share but, in fact, I do.
There was a question here a few days ago by a woman
in a mixed marriage. She was bothered that (seemingly)
a lot of people out in public seemed confused or dumbfounded
when they saw her and her husband together,
and they were particularly curious about their (beautiful) children.
A few people, including me, told her that the behavior she was describing was, in a large part, connected with WHERE they live.
That, if they lived in certain other places, they would not be faced
with this kind of public behavior toward their (unusual) family appearance.
So . . . I wonder if at least part of the situation here, with GEOY's brother,
may be associated with where they all live. GEOY has shown sensitivity and compassion by letting us know that brother has been having some problems, in his marriage and in other areas.
So, she's somewhat cutting him some slack for "losing it" with her son.
But, in Texas, where men are men, and the law of the frontier
isn't so far in the past as in, for example Boston or Philadelphia,
perhaps brother felt more entitled/permitted to go to physical violence
than he would have in a different environment.
Which is not to excuse his behavior, of course.
Just pointing out one more element that may have not been considered.
Back to 16-year-old. The original request was from this particular uncle.
So kid SHOULD (doncha love SHOULDs) have made a particular mental note (or better, on paper) about uncle's order.
When kid started getting overwhelmed with other orders,
he or someone should have written them all down.
I wonder if maybe he made some notes about all the orders
that followed Uncle's original request but didn't write that one down
because he thought he HAD it, or . . . . whatever.
Of course uncle's behavior was inexcusable.
But I don't think I'd call the police on this.
I think a meeting among the adults to confront brother
with his behavior, with discussion of what options
they recommend for him to work toward getting himself into
a more appropriate way of being when among other people.
Teen son should be given an opportunity to express his anger,
resentment, whatever, with adults other than this uncle.
The two of them should not have a face-to-face meeting
until uncle has had a discussion w/adult family members
as described above, and has expressed an ability
and intention to 1) apologize to his nephew, and 2)
learn some techniques for dealing with his temper/flashpoints.
just my 3 cents.