That's a good question. I believe that if your brother has made up his mind that he is going into the Marine Corps there is little that you can do to change his mind. All that you can do is support him in his decision. Be positive about it and hope for the best.
A Marines recruiter will not intentionally lie to get you to join. However, they are taught to persuade you and in the course of doing so they may stretch the truth (i.e. your chances of getting a base or a job that you like over others).
Children do not affect your ability to join the Marines.
if you have a criminal record can you still join the marines commando
No. if you have asthma you cannot join the Marines, sorry
No
No
Yes
Yes.
Yes.
No .
No.
http://usmilitary.about.com/od/marines/a/weightmale.htm