You cannot buy the Scratch software on it’s own anymore, so you would have to buy an external sound card such as the Audio 6 or Audio 10 from Native Instruments. This comes with the software.
Ok, so he would have to have something on the list that lets him qualify for the upgrade, but does he? I still don’t see anywhere on there that enables you to buy Scratch software on it’s own, so please elaborate on your statement.