bad self confidence, nerves, over thinking every pass sounds a lot like poor, or wrong, motivations. manager is suppose to address this.
And if he was a programmer and they were machines, he could. However they are humans the whole lot and there is no magic trick to make them forget their struggles. You could compare it to war veterans who get therapy... sure, might help, might take many years rather than a half-time break, but in some cases the traumas stay for life. Thats not because the therapist struggles but because humans are complex creatures.