When Brown goes straight up with his body at the free throw line and gets his nice release, he is actually a very good free throw shooter. His problem is he leans forward and back and jumps in the direction he leans and it messes up his shot. His form is good. His balance through the form is all over the place. Look at how many times he is leaning into that FTA and shoots, his whole body leaning forward and he stays grounded by his toes as the rest of his body pushes into the shot rather than getting the shot naturally straight up.
I could see where as the game slows for him, he ages, he matures and finishes growing into his body, that things balance out for him and he becomes a very good shooter from three(+40%) and good from the line(+70%). His form looks solid and consistent. It's his balance that is off.
Meh...maybe not but I am hopeful. Kid is smart. We will see how he matures from his struggles this year. Clearly this looks mental and not physical or lacking in talent.