A, Sit down with your father and go over the letter/contract. Then compose list of what you want done w/the house. If he thinks you are making it difficult to sell here's what I would do:
1. Point out that it would be beneficial to both of you if he would take some time out of his schedule to come over and do yard maintenance (this would help w/the appearance).
2. Point out that it would be beneficial to both of you if he were to come over and do inside maintenance as well. Some painting, carpet cleaning, even helping with the cleaning up a bit.
3. Point out that he can come over and get the pooch and take the dog for a walk or schedule a friend to keep the dog during the walk thrus.
4. Point out that it takes two to sell a home and if he wants it sold, he will need to do his share.
Now, about the health insurance. I was in the same boat as you, but once my h started acting like the butt, I carried him on my insurance plan from December 1999 to the end of December 2000. I advised him in November (open season) of 2000, that I would be removing him from my plan and he would need to get his own. I could have been a spiteful witch and dropped him the day he walked, but I didn't.
A, you've carried him on your policy long enough. You've done all you can to be patient and compassionate, it's time to look out for you and your children. Advise your lawyer to notify his lawyer that he will no longer be carried on your policy, effective the first pay period in January. He's got time to get his own policy.
A...don't worry, if the house sells, he will fritter the money way in record time and still be whining. If you can sell your home and find a nice place that you can afford within the same school district, go for it. I think you've done more than your share in dealing w/this problem. There comes a time when you have to fold and really focus on you and what you need to survive. Nothing says that you can't leave the door ajar, but that doesn't mean you have to be a door mat either.
Put everything in writing and advise your lawyer that's it and you are done negotiating....time for your h to step up to the plate and act like a man instead of a spoiled brat.
Keep posting....you are going to need the support in the coming months.
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.