Birdman14's son was a unicorn (an exception) that earned a two-way player opportunity at the D1 level. Very, very few are given the opportunity and can hold onto that opportunity. His son did, and was very good at it.
High school is a different matter entirely. The best hitters hit regardless of position. Accomodations are made for primary pitchers that can hit in high school. My oldest son played 1st or DH as they needed his bat. He was the 3 or 4 hitter his junior and senior high school years and was an all district DH. He did not bat once in college. His head coach had 17-18 position players that (presumably) hit better than my son and practiced hitting every day.
I hope all is going well! Sorry I don't get around here as much lately.
While my son's situation might have been a "unicorn," most of the middle to lesser D1 conferences have a player or 2 doing what my son did, or at the very least pitching and DHing (you might even say the college DH rule is somewhat promoting this strategy). My son still did all the hitting and pitching required, he just did some of it on his own time. This was much easier in his first 3 years when he was a relief pitcher only. When he was a weekend starter, it was pretty brutal.
I also remember that a team in the conference your son played in, had their top pitcher doing the same thing. He is currently playing AAA with the Yankees organization, as a hitter.
My point is that on my son's team there were not 17 or 18 other guys that hit better than him. And while it is unusually, it does occur with certain coaches who are open to it. I wouldn't want to discourage a player from pursuing this if the opportunity presented itself and it was what he wanted to do.
Would I recommend having my son do it again? That is a completely different question...