Unless I'm missing something, I don't see where he's unhappy w/his current life from the conversation that you had. He's relieved that you've filed and are taking the bull by the horns. He didn't want to file because it would have cost him more money. Yep, the person who files, generally has to pay more in costs.
As for his interest in the girls, it was to see where they are at in their current day-to-day living and he was curious to see if your D20 was in college and wouldn't come out and say it, but wanted to know how you could afford to send her. I do find it interesting that he's looked up where you are relocating to. Funny, he's shown so very little interest in his old life and now he's finally showing just a wee bit of interest because quite frankly, he thought you would be right where he left you and you would never do anything w/your life. He has no clue as to the person you've become.
Heather, don't allow that "posting from the alien" get you down. Continue to move forward and once everything falls into place, your life will be so much better and you'll know exactly what you are entitled to and when you should get support money and there will be no of this nonsense of having to beg him for things (hopefully).
Keep your focus on what needs to be done for your trip.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.