I also drive an hour and fifteen minutes one way on a good traffic day for my mental health care because of quality issues in my area. I was also a teacher, however, and I realize how much that time your son has to miss from language arts can effect him and now you are talking about more time.
I don't know if a letter of complaint will fix anything, other than give you a voice which may be what you want. Your options are difficult no matter which way you turn. I hope what every you decide to do, you will be happy with the care you find for yourself and your family.