In essence, what he's after is some form of stock control - So if an item of which he has 100 units sells on Amazon, it automatically / instantly deducts one item of stock across Amazon /eBay / his own website / anywhere he has it listed for sale.
There's some proper professional solutions out there that handle the above (amongst other things), but they seem to be a) very expensive and b) unnecessarily complex for what he's after.
He asked my opinion on this mob - http://www.neotericuk.co.uk/
But I wouldn’t know where to start - Not something I have any knowledge whatsoever on!
