At 41 you know most of these programs are full of empty promises. My friend did this course and was NEVER able to find a job. No one does this stuff. Office managers hire people to do their billing but since it's soooo important that not even one single number be wrong they don't hire anyone random.
A friend of mine was in the medical field practicing and one of the office staff made an error and used old codes for their billing for months. They ended up being sued by Social Security and insurance companies and more. The docs were all sanctioned and their licenses suspended until they paid back every single cent of money they'd been paid for that whole time period. Hundreds of thousands of dollars were paid back. BUT one or two of the docs couldn't recover and is now working at a menial job and not practicing anymore. That's how important codes are.
Jobs that you can go to school and learn in less than a year....call your local Vo-tech and ask them about short term programs. Such as nursing. Some vo-techs have 9 month programs. You could also do something medical like Phlebotomy but you will be working shifts and weekends.
If you're heading for divorce you need to realize you have to go to work now and go to classes after hours so you can eventually make a higher income. If you're not working now he can claim you have no income and he can get custody of the kids because you can't support them.
I'm assuming that's why you want the education and job as soon as possible. Go find the best paying job you can, put the kids in child care or after school child care. Get that income coming in. Then enroll in some night classes and get the education you want.
Working at home when the kids are in school isn't a bad idea but they will be out for summer vacation soon and then you won't be able to work at home. Medical coding can cost someone their career and they won't hire someone who can't give 100% of their attention to what they are doing.
Finding out what jobs in your area are needed will help you find the best route to go.