Re: advice needed, discipline...
No prudent captain prohibits his crew from questioning orders. Good crew sometimes have better ideas, sometimes notice things overlooked by the skipper, and sometimes note that the skipper has made a mistake.
Any man who says his brain, eyes, hands and mouth are always perfectly synched when his mouth is open is either lying or delusional, and even the most perfect among us, the experienced seagoing captain, isn't exempt. Thinking starboard and saying port is a not unusual mistake.
My policy has always been that anyone can question any order...once. If I issue the order again immediately after the crew's question, I have considered his comments, and his urgent attention is needed to doing what the hell I ordered.