Not mentioned above is almost all high school "kids" will be 18 when the draft comes along. It's really their decision. All families are different. You might think of what you will do if your son has ideas different than yours. (NOTE: You in the sense of the general you, not a specific you, or you's you.)
What I gather the minors for a just out of high school kid is a lonely place, teammates change weekly, they are always trying to bring in somebody better than you. Part of the discussion with my kid is that you can't win a conference championship in Rookie Ball, you can't win a Regional or go to the CWS in low A. So you get drafted and get a $100,000 (take away or add a zero to fit the circumstances, if any), don't you think you would get at least that after three years of college?