Yes, baseball recruits are at a major disadvantage. Basketball and Football players post their offers and get to sit on them for months, even years. As Goose mentions, for baseball the risk is all on the player.
You have every right to ask your questions. However, you can either get straight up answers from a great coach, or you could end up turning him away and losing an offer. Or you could commit and your son continues to blossom and maybe lose better opportunities.
I would sit down with your son, be open to him about your concerns and what the recruiting process is really like. He may not want to hear it as he's young and probably extremely excited about the offer. But it is what it is, so you should both be on the same page with eyes wide open.
Good luck!