And as I already replied there. Neither is it general practice to ask people no longer working for a company but for another company in the same business on their work. Generally contracts even forbid to do business related work or publications without asking your current employer first (especially in the IT). Furthermore does his remark (if he really means it) suggest, that the code is badly written and they failed to document it (I don’t say it is), because otherwise it would not be necessary to ask them about the code.