I'm serving Active Duty in the US Air Force - everything I will discuss herein is applicable to all 5 branches of the US Military. Additionally, my boyfriend is serving AD in the US Army, so I am a military girlfriend of sorts.
First of all, a dishonorable discharge can only be assigned to a case if the service member in question is court-martialed, so don't assume he'll be dishonorably discharged unless he does something very intense, IE he goes AWOL.
A dishonorable discharge is pretty bad. It will stay on his permanent record forever; whenever he fills out an application, there will be a spot saying, "Have you ever served in any component of the US Military?" and he will have to check "yes." If the employer runs a check on his military records, they'll know he got a dishonorable discharge.
Anyone with a dishonorable discharge is entered into NICS, which is what police officers look at when they pull you over. This means he will be permanently ineligible to possess a firearms license, and if he does get a dishonorable discharge he will have a lot of difficulty getting a job in any civil or governmental position.
It's not like he has to wear a scarlet letter on his chest. :)
Please understand why your husband can't come home: If he were to leave, it's not as if the Army could just send someone to replace him. His spot would be empty, and that could put other Soldiers in danger.
I totally understand how hard it must be - it's hard enough that he's missing the pregnancy, and now you must be terrified of complications and of delivering alone. But you're an Army wife; that means you're Army STRONG, and you [both] can get through this! Is there any way that you can have a brother, sister, father, mother, father-in-law, mother-in-law, cousin, uncle, or grandparent present? I know it's not the same, but at least it's a comforting presence.
And maybe someone could film the birth and send it to him? Remember, other Army wives have gotten through this before, and you can too.
As Cordelia said, the paperwork, etc. required for a dishonorable discharge can drag on for months. I've never seen one last 6 months - but I have seen several last for 3. If the servicemember in question is in Iraq, it's likely to be even lengthier.
Goodness this is getting long! :X
Other than honorable discharges, general discharges, etc. are much less serious. He would have difficulty re-enlisting in any branch of the US Military (and it sounds like he's a good Soldier who enjoys what he does), and he would have difficulty getting any type of a governmental or civil job.
Again, however, he wouldn't be able to be back by November. These things take quite a while to process. I know it's really tough, but you're probably going to have to deliver without him. I looked into your other questions and saw that the condition you have is quite common. My mother had it in both her pregnancies; with me it eventually straightened itself out and I was delivered vaginally; with my sister, she had to have a C-section, which is not a big deal. With today's medical technology, there's absolutely nothing to worry about. I know that isn't much coming from me; you don't even know me - but talk to your doctor about it more in-depth.
AD in USAF
Boyfriend is AD in US Army