Passport requirement is a bit weird, unless you're a non-US citizen. What's your citizenship status? (Assuming you are located in the States and he is elsewhere.)
"Stop distributing the program that his is based on"? So you have an existing product, and he wants you to stop selling that too? Unless this was expressly agreed to before hand (doesn't sound like it) that's a rather bold demand. Especially if you derive income from the existing product, have an installed base of users, etc.
If the money's only so-so, I'd consider taking a walk. It's not worth keeping a business relationship going with somebody who'd make these kind of last minute requirements. Chalk up your time/work investment as a lesson learned and move on.
On the other hand, the money might be so tempting that you'd be willing to stop selling your existing thingie. Assuming HIS business model supports income for you, is successful, and you trust him to pay you in the future. All real concerns, especially more now since he has seemingly modified your informal agreement without consultation. That's a sign of bad faith, based on what I understand so far.
At this point, I wouldn't sign ANYTHING without passing the proposed contract through the hands of legal counsel. A contract review would take a few minutes and is worth whatever you pay for it to avoid future headaches.