I would also think maybe they see him as a work in progress. The coach may want to see how well he learns and responds. Without pitching lessons ever, he could make great strides with strong instruction. This may be his shot at P5. A personal invite from a P5 HC does not get any better. An email from RC is one thing but invite from HC and him wanting to see him with their PC is another. This may be what it takes to get offer. But also your son must ask the question is he willing to move from Catcher to Pitcher Only. That is a big jump because it means going from playing every day to once a week or less. That is a big difference for a kid who is used to playing all the time. I don't see a P5 letting him do both. Big decision but life is full of them.