Is it true that if you get a DUI and you are in the Coast Guard...

Yes, but don’t forget that you (the one who has the DUI) are also subject to the penalties determined by civilian courts. A captain’s mast is just a hearing to determine culpability and possible punishment. for the service member in terms of violating military regulations.

Not certain of rules in the CG. It might be that a Captain’s Mast is an automatic thing from the view of Drunk and Disorderly, or Failure to Obey an Order (a standing order qualifies) might apply. It might be that since you were detained for DUI, you were unable to report when you were supposed to. There are a lot of ways this could play out. Typically, the military will support the local police near the bases because they don’t want to be known as bad neighbors. Because of that they will add additional punishment to someone that is arrested off base.

So that means you are automatically booted out of the CG
for your first offense no matter what?

Captain’s Mast is a non-judicial punishment. You would not get booted out of the CG by going to a Captain’s Mast. At the Captain’s Mast, the commanding officer determines the facts of the case and sets the punishment. But there are limits to what he can set as punishment. He can take a rate in pay, he can confine you to the barracks or the ship for a period of time…things like that. He cannot fire you, give you a dishonorable discharge, have you flogged or have you thrown into the brig. For those things (except flogging), you would have to commit a crime so egregious as to warrant a Court Martial. That is the next step up in the military judicial system. You CAN get dishonorable discharges, sent to federal prison, spend an extended time in the brig, etc. if you go to a court martial.

Our son has told us that he will be ordered to leave the CG because he did get a DUI.
We as parents are brokenhearted as he has been in for 3 years and has gotten 2 LOC
and is now a MK2 and wanted to make the CG his career. Yes he messed up royally
but has been so outstanding in his short time in and has no other marks on his civil
record. He retained a lawyer and has a court date in April and will continue to work
in the CG with nothing changing until the civil side is decided because otherwise it
would be double jeopardy. He says that it doesn’t matter if you are not guilty of DUI
for whatever reason the lawyer can find that you automatically are out of the CG
and you will find out all the details at the mast after the civil trial in April. He thought he would be ordered to stay on his ship but that didn’t happen…everything is the same asit
was regarding cg work and routine. If he gets an honorable discharge can he join the
air force? Even when the lawyer makes the DUI go away on his record the CG still has
a recording of it. All that training gone to waste. I wonder how many CG do they loose every year because of one “mess up”? According to our son..yes anyone in the CG who gets a DUI gets booted. He was never handcuffed just took to the police station and he even had a gun permit and had a handgun in the console but they gave it back to him at the p station. Never checked it—why would you give a DUI victim his gun back? Never locked up..just had to leave the door open when he went to pee! The lawyer was astounded at it all and our son’s career is over. What do you think?

I hate to say it, but it sounds like there is more to the story that you are getting. I was Navy which is somewhat different from CG and I got out more than 30 years ago so times may have changed. But the Uniform Code of Military Justice hasn’t changed THAT much. At least I don’t think. A policy like that in the CG makes no sense, for the reason you stated. They have spent a bunch of money training your son and I can only imagine they don’t want to waste that money. A policy like that would be a bolt hole for tons of people that would want to go in, get trained into something, and then get out without a lot of effort. A branch of the military tossing you out is not done lightly. There are obvious things such as the violent crimes that can get you tossed, as well as other issues like medical. But they don’t just say “well, you screwed up so you’re gone.”
As I mentioned before, a Captain’s Mast is a non-judicial form of punishment. It is local to a specific command. It is the commanding officer (CO) taking care of low level screw ups at that level to keep discipline in that command and in line with the expectations of the broader service (in this case, the CG). I have known various of my ship mates that went to Captain’s Mast. The punishments can be painful to the person, but ultimately survivable. As I said, I have seen restriction to base or ship and loss of rate (E5 down to E4, for example). And Captain’s Masts, in the long run, are blips on the screen of a service record. If you transfer to another duty, that CO can see that you went to one and will have some of the details, but typically that doesn’t haunt you. The next step up is a Court Martial. That is the service taking legal action in a situation that is severe enough that imprisonment or ejection from the service may be warranted. I have known a guy that went to one of those, as well. His charge was malingering, which is trying to hurt yourself so you can get out of the service.
I did a little research and found this link:

http://www.jag.navy.mil/legal_services/legal_services_faqDEFENSE.htm#dq15

That gives some explanation of military punishments. Since your son has been in the CG for less than 5 years, he COULD be released from the CG without a Separation Board, so long as it is with a General Under Honorable Conditions or an Honorable discharge. I’m a little deep into things and am not certain of the order of things to get to this point. I found another site that listed the maximum punishment that can be given by a Captain’s Mast and discharge from service wasn’t one of them.
As for being able to enlist in another branch of the service, that is uncertain. That gets into the bureaucracy…if a form is filled out a certain way, the answer is yes, they can. If it is filled out a different way then the answer is no, they can’t. If the discharge is Honorable, I would venture the answer is yes.
There are a number of websites out there that give some guidance. I found one where I could chat with a military lawyer, but they wanted a $5 fee. Sorry, I figured you could pursue this if you wanted.
It seems this is really worrying you. I would recommend doing as much homework as possible. Get facts. The military operates on standard operating procedures that aren’t often deviated from. Find out what those are…they should give you answers you are seeking. As I said, the story I am hearing sounds suspect. There seems to be more to the story than meets the eye.

Thank you seawulf575 for answering what you know and caring.
Blessings to you in 2018.

And you as well, MooCows. I hope this all works out well for you and your family.