PO vs two position player

First, go where the coach says to play.

Second, a college will recruit roughly one pitcher for every single position player recruited - so more pitchers proportionately are recruited.

Third, unless he hits really well, he will probably be a PO at the next level (assuming his pitching is good enough). Two way players are very rare in D1; the best of the best. Your post says it all - in HS he plays second because of the team's lack of depth (my S was a left handed HS SS when he wasn't pitching - doesn't say anything other then no HS depth); but on a better team he is a PO.

Pitching coach says go PO?  Hmmmm.  Shocking

Look, this is different for every player.  All things factor in.  You will hear often here - usually the game will tell him when to stop at either (keep playing until game tells you otherwise).  But the player has to do what he loves/wants to do.  It sounds like your son's pitching skills are his strength and his best shot at playing at the next level.  But there is nothing wrong with focusing on pitching while still playing as a position player at times.  He just has to take the necessary precautions to protect his arm.

The opposing argument is that he would have more time focusing on honing his pitching craft if he was PO only.  He could do more pitching drills, bullpens and pitcher-specific workouts.  But how often can you pitch?  And you can make it a point to do more pitcher-specific workouts if you choose anyway.  If he loves both, let him enjoy both while he can, while still taking reasonable precautions to protect his future path.

BTW, I totally agree with the point Goosegg makes about going where the coach tells you - where the team needs you.  In most instances, good communication with HS coach will allow for proper arm care measures while going both ways.

My son was recruited as a 2-way player.  RHP and SS.  He hit .478 with 35 RBI's and 4 HR's as a senior, league player of the year...and an all-state selection.  His recruiting coordinator is also the pitching coach.  He is giving him a shot at being a 2-way player....though I'm not sure he's thrilled about it. He wanted him as a PO.  It's looking more and more like his chance at playing the field will be at 3B not SS...as they brought in 7 SS's this year.  Nothing against second basemen, but I'm not sure where a HS second basemen would fit in on a college team. I'm guessing your son will be viewed as a PO by college coaches....especially when in your words "he isn't thrilled with it".  Very few college coaches recruit 2B guys...they just take SS and move them where they need them. 

My 2016 was in a similar situation the last few years of HS and Travel ball - he had been a RHP and 3B but was switched to 2B to save his arm between starts and eventually they just stopped putting him in the field for the HS and made him PO (which seems to be what they do with all but one of the starters the past few years).  His travel team the past two summers was coached by a current D1 assistant coach and he had him do both - and encouraged us to have him continue to play the field and bat this summer.  So he started the summer doing both.  About three weeks into the summer season he decided on his own that he wanted to focus on pitching and honestly it made the recruiting efforts much easier on the family.  

As a PO we were able to schedule his starts over the summer and pick the tournament games where the coach thought we'd have the most schools watching and he was also able to attend camps/showcases mid-week and pitch.  POs also get more innings at camps than two way players (usually 2 or 3 innings for POs vs 1 for the two ways).  I can also say that I thought he pitched much better at the events he was PO vs the events he did as a two way player.  

So from our perspective it was easier for us to manage and for him to stand out as a PO - for the summer recruiting season.  

All that said and he's back to doing both in the fall - we signed him up for a fall team that had him play 1B and close the first tournament the played.  He hadn't played 1B since freshman year.  He said he had fun and wants to do both all fall so we'll see what happens.  The school he is focused on is recruiting him to pitch but also told him he's free to try other positions as well once he gets there (as long as he continues to pitch). 

What level is your son looking at for college? 

Schools need to recruit a lot of P and not 2B who are only decent hitters.