Some people are just looking for a way to get their money out of what could be "ground breaking findings". By having you pay him for his "services" he ensures that his "expert knowledge" is paid for if you then turn around and use this to make money in the future. It also seems like he feels that his advice is too good for the paper which is why he would need to "hold back and question your choice to submit it".
To me at least by the way you present this, he seems arrogant and just looking to make a quick buck. I have found that generally, people are willing to help someone out and offer advice. Some times, they might even strike a deal with you if they think that your subject is worthy of pursuing outside of academics. Like say, you have a thesis paper that will help lay the foundation to later provide technology that will drastically change the way hearing aids work. Someone might say hey, I will offer you help and provide you X, Y, Z if we do this and pursue this farther than academics if you will provide me X% of any profit made due to this. I had someone do that to me actually when I was looking for help with my senior college project. My group turned them down because we felt we shouldn't need to give away anything for scholastic help.
Also as a side note, he may have also miss-understood your intentions of going to him. He may have thought you wanted him to basically rewrite the paper for you, instead of providing criticism (though I am sure you probably clarified that at some point). Either way, he doesn't sound like a good resource to go to. I have found that when teachers refer you to students like that, most of the time they are looking for payment. You may be better off doing some googling for anyone local that might be an expert and contacting them, seeing if they will be willing to sit down over lunch and look it over (maybe even offer to buy the lunch as courtesy of their time). Though it probably would be easier if you emailed them the paper and they can do it at their leisure.
I have found that established people in the fields are more generally willing to help out college students for free and provide quality feed back. They don't need to make a name for themselves because they are already in the field, and generally they want to encourage people to have interest in their field. It is how their field grows and in turn better technologies are created/provided.
Sorry for the TLDR but hope my 2 cents help!