L.G.
Most Bar Associations have a referral service where you can see an attorney at a very reduced fee. It is the first visit at around $35. interview the attorney and see if she is the right person for you.
Your children must be old enough to know what he is doing. If you were divorced 7 years ago go ahead and tell them what is coming up and how worried you are. They ought to learn as much as possible about their father and his motives. They are teenagers. They can give him a piece of their minds. The can tell him off or they can go to another state for school where it is hard for him to see them or refuse his phone calls. These things they must do on their own not prompted by you. Life pays you back remember that.
My ex cheaped one of our children so badly that although she let him walk her down the aisle she barely sees him.
At $75 dollars an hour your pig is hardly a pauper and keeping an attorney on retainer takes quite some money.
I hope you get a female judge who'll take him and his lawyer apart