Im of the mindset that he should continue as a two way player at this point. Things may change once he makes the V team at HS but until then leave all your options open. I am going to use my 2017 as an example...
Up until this past off season he was a 2 way player. P, IB and some OF. Going into the off season his HS coach mentioned that next (this just started) season he most likely would be primarily a P on Varsity and play some 1B in the JV games (if he wanted to play a position). His travel program has talked with him about his options in college and have stated that his best chance is as a P, but he should still work on his position play, "just in case".
Our travel program has a pretty aggressive off season program and my son concentrated on Pitcher workouts, assuming he is going to be a PO heading into the season. He did attended 1 position player skill workout a week. Most of our programs off season work is strength and conditioning but they do sprinkle some skills in. He also worked out with his hitting coach 1 day a week plus hit off the tee at home in the garage all winter. All, "just in case".
Fast forward to this past weekend. HS coach stops him before practice. Tells him to head over to position player workout instead of pitchers workout. Also explains to him that unless he is scheduled to throw a bullpen he wants him working out with the position players. Coach goes on to explain that his is very deep in pitching this year (as compared to most years) and that my son is about 4 deep on the roster. He is sitting behind a D1 MLB factory school commit, a D1 Big 10 commit and another player with D1 potential who has decided to play college football instead. In addition to those 3 PO's they are carrying another 6 or 7 POs as well. At least 3, if not 4 will eventually commit at some level sometime over their HS career. Going into the season he thought my son would be the number 4 starter or his primary closer, but as he is so deep in pitching he has the luxury of moving some kids around. He has a hole at 1B that needs to be filled and wants my son to play there as his primary position. He still wants him throwing and plans on using him in middle relief, or to close, throughout the season, but he has a real need at 1B (long story).
What I am getting at with this long story, is as you move into HS you have no idea what the needs of the team are going to be. If you specialize into a PO too early you may close some opportunities for yourself as you move forward. Yes, at some point, you may need to specialize but if you have the ability to play as a two way player I would consider delaying the decision to specialize as much as possible. Now if not specializing is hurting the player then yes, specialize. But again wait as long as possible to make that decision.
BTW, got to give props to the son. My wife ran into the coach after practice this weekend (she works in the same district, and they get along well). He mentions to the wife that he was really impressed with my son and his attitude this year. He is looking to him becoming a leader and hopes others will pick up on his work ethic and attitude. My son basically looked at him when he explained the switch and said "yes sir, whatever needs to be done for the team". Coach also mentioned that he talked with another player who gave him a completely different attitude and lost out on the chance to start another position as he was only concerned about himself.