Steely, I found the lists of every place approved for various types services and what "pool" of funding is approved to cover it in our state. It was online and I'd bet you could find this for your state too. I will forewarn you- it can be discouraging. This is where I realized that the reason difficult child would only get behavior mod/behavior contracts if he got any type of in home service is because being on probation, the pool of money was Department of Juvenile Justice money and that is all it pays for- it would not pay for any other type of mental health treatment. And if it failed, we get blamed and he would get committed to Department of Juvenile Justice anyway. It had nothing to do with tailoring the treatment to the child and didn't matter which company they got the treatment from.
But you/M don't have that issue, fortunately. Now, the way I found this- I started with the state governement website and poked around the links for mental health care and services for "at-risk" youth (this included transitional services for older teens), and found the link for the people in the system to use to find what what their pool of money would pay for, company names, types of services, etc. They listed group homes, various types of mental health services, etc.
One advatage is that if they are "state approved", they have to be accredited, or checked by the health dept., or at least somehow proven to be a legitimate service provider and meet minimal guidelines.