Money up front is never good, especially 6 months in advance.
Taking money up front to live off of is a horrible business practice.
He's going to crash very soon. I would give his info out and save people the trouble. He's basically just borrowing people's money for free to live off for 6 months...
No matter how you look at the other interested party in this deal, it will not change the fact that you are trying to justify defaulting on a contract that you made. That is on you.
I agree with both of these statements.
If this modder does a fair amount of work (more than 1-2 jobs a week), and everyone pays him 6 months in advance, and he has no money? His flame out will be epic.
Hopefully he won't have your money AND your knife when the curtain falls on this game he is running. It's sad that he has put himself in a trick-bag where modding more knives costs him money, but taking more orders makes him money. Can't see this ending well ultimately.