A friend told me a story that reminds me of a problem I see frequently. My friend runs a small business with one major supplier providing many of the parts and tools. The supplier is a privately-held company with several million in annual sales. Each month the supplier renders an invoice to my friend's company for that month's purchases. The invoice is computer generated and details each purchase for the month and the cost. At the bottom of the invoice is a hand written amount for the total discount for that month's invoice and a handwritten "total payable".
My friend explained to the supplier that a total discount prevents him from determining the real price per item, and thus he can not compare prices with competing suppliers. The supplier explained that the accounting department can not produce item level cost net of discount. One can only wonder how many sales are lost each month where this supplier is the low cost provider but the customers do not know it.
The accounting department is run by a relative of the owner in order to reduce the risk of employee theft and herein lies the problem. When you hire relatives perhaps you reduce the risk of theft, but it makes it much harder to make improvements to systems and procedures when you have to worry about embarrassing a family member (who can not make the changes or does not understand the new application or system). Also, if the relative is incompetent it is much more difficult to replace them. Private equity funds and venture capitalists strongly discourage or prohibit hiring family members for exactly these reasons.
A better approach is to put in the appropriate controls. For example, if your concern is employee theft and you are worried about "fake" suppliers (a common way to steal money), put in a policy that every new supplier has to be approved by the owner and every month get a report that lists every account payable paid with check number and a list of every check written that month. Every check written that does not match an approved supplier is then scrutinized. If you are worried about the check payee being changed after it is written then use cancelled checks for the month rather than checks written.
Successful companies rely on controls rather than family members.