To begin, I want to sincerely thank each of you for the time you took to give me very thought-provoking responses. I really do take time to think about each of them, to examine any unknown motives I may have had or to try to understand how all of his experiences may have influenced how he sees things. It's absolutely fair to say that the mom I am now is not always the mom I have been. (I guess we grow along with our children). So I could understand how this was not as linear as it could seem. I also knew this wasn't just a matter of a spoiled, entitled child...that it was more than just an issue of he had some growing up to do.
In reflection, I realized that I had gotten myself into a bit of a pickle. I had wanted him to own the responsibility of making this choice...I genuinely did not want to be an influence in whatever decisions he was making. Even though I am helping him, I want him to also feel both the joy and responsibility of this being his thing, his house. But I had never imagined that my help could possibly help him to do something that was harmful, to be able to get himself in a really bad situation. And that's what I saw in that particular house. It was just going to be getting him in over his head...and I knew it in every fiber of my being. I couldn't even understand why he was moving in the direction he was. I knew something was motivating him (because he really does have a good head on his shoulder - and that's the only reason I would have ever offered the help)...I just couldn't figure out what was driving him. I now know and I'll that below.
The second piece of this was HOW he spoke to me. It wasn't offensive to me if that's how he felt. It's not even offensive to me if he tells me in less than constructive ways. I truly am just thankful that he feels he can tell me. But there is a point where it becomes not just disrespectful but even cruel. It was cruel that day...and that's just not ok under any circumstance. I've tolerated some of that in the past (basically, set the bar low)...but I'm now also not the same *person* I was back when I would overlook or dismiss that. So that was also something that needed to be addressed and new boundaries clearly communicated.
So..to update the situation. I took a break for a few weeks. When he had accused me of giving him the money to control him, I took the money off the table at that time. It wasn't so much "I'm not giving you the money" as it was "then we need to take the money off the table". IOW, it was somewhat ambivalent. I think it left him in a bit of a quandary. The house he was looking at also went immediately under contract - which also took some pressure off. It gave me some time to back away and him some time to cool his heels. We didn't talk for a few weeks, maybe a couple of texts exchanges here and there. He tried a couple of times to "mend the fences"...but if he mentioned a house or money then they were very short conversations. I don't know if it was the right thing or not...but I just felt that I didn't needed to talk to him about those things until I sensed we were in a place to have a really genuine place to really discuss ALL of it. I didn't want our "resolution" to be guided by his still trying to get a house.
When we did finally have an opportunity to have a genuine talk, I just shared with him my concerns and how my original intentions had gone wrong. I told him I was still willing to help him...but not within the same constraints I had set prior. While it's up to him to pick location, house style/amenties, etc...but the money would not longer be cart blanche as I had first presented it because I didn't want to be in a place where I felt I could actually be helping to later cause him a bigger problem. He can take it or leave it. He can also either trust or not trust my motives. He's certainly still in a place to buy a house without any help from me. But if I am to help, then, for my part, I have to feel that I am actually helping. I also had a very pointed discussion regarding the way he talked to me. He wanted several times to suggest that we were both wrong but I didn't let that distract from the bigger overall picture. There was certainly a considerable difference in how we both were wrong so I didn't allow those to be the same. I think that part really surprised him...but I have definitely sensed a difference in him since that discussion. He seems to have a different appreciation for me...and a new regard for the concept that I am actually desiring to help him. I don't know...we'll see in time.
All that to say, the house hunt is somewhat on hold - by his choice. He told me a few weeks ago that he had been holding in his current job, just so that he would qualify for financing. I knew it had been his plans to find a new job once he bought a house...but I didn't know how miserable he was in that job. I can now see that this was probably the urgency and desperation that I had started to see in his searching. He has since quit that job and seems to be in a much better mental frame of mind. He's back to being the more logical and analytical child that I first offered the money to. I feel much better about this place. It's hard to explain - and I know you parents will already understand - but I could just tell that something that was motivating him was not the right thing to be motivating him. He's still continuing to look at houses, will send me some listings and I'll send him some. But it has a much more "leisurely stroll" feel to it than a "sprint to the finish line". I would genuinely love to see him get in a home...but I also very much believe that when it's the right time, it will happen. And when it's right, it won't be clouded by so much difficulty and angst As far as I'm concerned, so long as it's not surrounded with angst, I truly don't care what house he gets. But I can also see in this time since things have settled down, he's already coming around to thoughts that I couldn't understand why he wouldn't consider prior (ie, locations). So in some ways, I guess maybe this is the process and maybe all of this has served its own purpose.
Sorry for such a long update. Thank you all again from the bottom of my heart. It really was all your perspectives that helped me to get to what was my own. 
Hope has two beautiful daughters; their names are Anger and Courage. Anger at the way things are, and Courage to see that they do not remain as they are. ~ Augustine of Hippo
Funny thing, I quit being broken when I quit letting people break me.
