I told him that. He said they have a pretty tight rein on their inventory so he isn't too worried about having to do that. I gave him fair warning though!
The other files - in case anyone is interested - were IM_PeriodPostingHistory, RA_CustomerInvoiceHistorySearch, AR_SalespersonCommission, IM_ItemCustomerHistoryByPeriod, and SO_SalesHistory. Since these are all written to during an invoice update, I'm guessing something went awry during an update. He had opened a case with Sage and they said to zip his data directory and send it to them, which also didn't work. And then he left on vacation for a day and left another in charge. By Friday, they were getting a little frantic.