Update:
His survey came out today and is completed. The tree is 90% on our side confirmed by his survey. He was out there this morning too. He said he thought the tree was on his side when he looked at initial plans when he started to plan the project. No mention of hearing otherwise from our arborist. He did mention he knew they were out there and that he knows them from getting them out there for a bid. He did take responsibility for it coming down and says he will "make it right". He also said "so it looks like this tree is 75% yours and 25% mine". I guess he thinks I don't know how this works at this point.
He is getting someone out today on his own to assess the value of the tree. He then said once we get the appraisals, I can let him know what we'd like. I didn't answer. Toward the end of the conversation, I explained to him, seeing as he's in the construction business and likely knows more people in landscaping and things of that nature, for him to let ME know what he's willing to do and then we'd see if it was reasonable. There is zero chance I'm starting any kind of offer to him.
So now we wait. I should hear from him next week. I've got all the information I need now. Hopefully he plans on making it right with something acceptable and we can be done.