Do you rely solely on the income from the business? Do you have any savings? No need to answer here, of course, but I would be VERY wary if you do. He doesn't share the financial information with you (which is really odd btw) so for all you know the company may just be in debt.
You're right that him asking you to do the project then completely forgetting it and not using it is a huge red flag. It may well indicate that he's not taking care of business as he should and asked for help out of desperation but can't even deal with that/has genuinely forgotten.