"My question is, if and when the therapist starts to talk about R, how do I respond accordingly? Do I give detail or do I keep it simple?"
This is for your son. Completely open and forthright honesty, holding nothing back. This has no chance of success for your S with anything less than that.
M(53), W(54),D(19) M-23, T-25 Bomb Drop - Dec.23, 2017 Ring and Piecing since March 2018