My son, also a catcher, developed yips the summer going into HS. He lost the feel of throwing the ball back to the pitcher, everything else was fine. Who knows what caused it - maybe nothing, maybe pressure from his travel coach or his high-expectations dad, or pressure on himself, who knows. He tried to work through it, lobbing the ball back to the pitcher, but for that summer the game became no fun, something he dreaded.
Around this time he complained about shoulder tightness and elbow soreness. In retrospect I should have shut him down. He was going through a massive growth spurt and grew 5-6" in a year. Everything in his body was changing weekly it seemed. He ended up fracturing his medial epicondyle and having shoulder tendonitis. I think it was TPM who said that yips are often the result of injury. I think she was probably right.
A lot of things changed after this. I told him it was ok if he didn't want to play anymore. He needed to know I was ok with this. He took a break from baseball and played HS football in the fall. He hit the weight room. I backed off and transformed into a supportive dad. He kind of put baseball in perspective and realized there were other things.
The following season he decided to play. He played with a chip on his shoulder, like he had something to prove yet nothing to lose. The yips were there in the mental sense (i.e., the worry), but he was able to throw. He was more conscious in bullpens to practice throwing the ball back the same way he would in a game. When things got shakey, he changed his arm slot or grip to mix things up. He maintained his PT stretching and warmup routines. Maybe most importantly, he was able to talk about it (with me, teammates, his HS coach). He had his "oh no, is it coming back" moments, but they faded over time. Like a lot of things, once you survive something traumatic (and getting yips during WWBA or USA Baseball is traumatic!) it isn't as traumatic the next time you face it.
He's playing in college now. Not to brag, but he's tearing it up. He still seeks out the guy who has trouble throwing and offers suggestions - it seems every team has someone, and he can see it no matter how they try to hide it.