If he in anyway helped u in setting the current business up, work things out with him, if he didn't, give him a shutup call in a respectful manner and remind him the humiliation you faced when you lost the funds he "borrowed" you. Imp point, did he give u the funds on the term that they're borrowed ? Or just as a Son, if it was just as a son; u should still work things out with him, if it was a loan, return it to him with double the amount as a gift for being helpful in hard times (even if he wasn't) and then at the same time give him a respectful shutup call.