Hi IrishMD, I used to do my own billing and have some experience with coding. It is pretty easy to learn, but as you know, it does not pay very well. You will be able to earn way more if you work part-time as a physician. If you continue to work as a physician, maybe once a week or even less, you will avoid the huge hurdles to re-entry down the road. In a few years, your children will both be at school during the day and the school district will be required to provide the services that your special-needs child needs. That will free you up to work more.
Your situation is described well in a book called "Opting Out," which is about why professional women sometimes quit. Some of the common themes are husbands with demanding jobs, husbands who need to move for their jobs, children with health issues, and inflexibility of the professional woman's workplace. I thought it was an excellent book.
Anyway, you are in a challenging situation, and I hope you are able to find a job -- clinical or non-clinical -- that will enable you to meet your needs and your family's needs. Good luck.