"So the text reads "your wife has informed me of your letter and its sad to hear, would like to meet one last time not as a jc, to be sure this is what you want." Would like to respond to his text with something very appropriate but can't think of any thing."
Here's some ideas:
"Please respect the fact that I have disfellowshipped you for being a proponent of false prophets. Discussing the sins of Watchtower Corporation with you would clearly be a waste of both of our time since you are a very low level pawn of the Jehovah's Witness clergy heirarchy."
"'...sad to hear?' Let's be honest, you've been aching to drag me before a jc in a windowless back room of the kh. You need to recheck the scriptures. Such matters were to be conducted at the city gate in ancient Israel. The account in Corinthians was written and discussed openly, in harmony with the instructions to conduct such matters before all on-lookers and before the congregation. Let's stop the pretense that any JW procedures are based on scripture. And let's stop the pretense that you have any real authority. 1 Cor. 11:3 is very clear, yet every clergyman, including yourself, inserts themselves as Christ's spokesman."
"Instead of meeting with you, perhaps I could meet with your wife and she could inform me of whatever it is that you have on your mind."
Frankly, I probably wouldn't respond. Was the letter that unclear? Does he have problems reading?
As far as the wife and kids, don't judge them too harshly. You are the one that has changed and woken up. They are still in the WT stupor. Make it clear that this change is for the better and that you haven't become the "stark raving mad evil apostate" that the scum bag elder wants you to become.