What advice would you give to someone considering getting out at 12 years of service to pursue a civilian career?

Have you looked into Army Nursing? There is AECP that will let you go to school and finish your nursing degree on active duty, and then there is ROTC that you could transfer into and finish your degree in nursing as a cadet. Then you would ideally come back on active duty, get that sweet O1-E pay, and finish you time on active duty and retire as a Captain at the least.
Either way, that AD retirement is worth its weight in gold when you consider the amount of money you'll make from your pension, concurrent receipt of disability (if you rate anything which most people do after 20 years), and money saved with Tricare. Over 40 years that adds up to a couple million for most people. Even if you retired at your current rank today, without inflation that would be a million in your pension in 40 years. Of course, when you divide that up its only $25k a year and you will probably do better once you are a nurse. But that's $25k a year for the rest of your life even when you are sick, injured, or out of work. Retire as a Captain and it's even more.

In my personal opinion I think the additional eight years is worth the investment as long as you are investing in yourself. There's no reason you can't become a Nurse on the Army's dime. While you're at it you might be able to transfer your GI Bill to your kids as well.

Bonus: you don't have to pay back any of that reenlistment money when you get accepted into a commissioning program either.

Tough decision with many factors for and against, ultimately do what is best overall for you and the family. I got out the first time as a SSG with 9 years active time. I was DA select for recruiter duty and I didn’t want to do that.

Worked in civilian world and decided I wanted to get my RN degree. Did ASN first, worked full time and decided to upgrade to a BSN. Used various options in the Reserves to help fund both of these.

Came back active after more than a decade away, my youngest a senior now, to go through the Army’s nurse anesthetist graduate program so I wouldn’t have to borrow a couple hundred thousand. By the time my payback was completed I had about 17 years active time. Finishing up my 20 this December 31. Getting out and coming back were well worth it.

You have already done more than half for a 20 year retirement. I would stay and stick it out as painful as this may seem now, in ten years you will have a guaranteed income. The military also helps with child care, in the civilian market, you pay and no one else really cares about your expense, you eat that cost.