There is a lot to say on this, but much of it has already been said. I'll add just one thing:
An important red flag (among all the others in your post) is the statement that he is "almost" done.
When any programmer thinks about that statement, it's almost certain to elicit a belly laugh.
If he appears to be "almost" done, it is highly likely that he is really around 50% done. Keeping that in mind should help you make your decision to walk away.
Comments
There is a lot to say on this, but much of it has already been said. I'll add just one thing:
An important red flag (among all the others in your post) is the statement that he is "almost" done.
When any programmer thinks about that statement, it's almost certain to elicit a belly laugh.
If he appears to be "almost" done, it is highly likely that he is really around 50% done. Keeping that in mind should help you make your decision to walk away.