Right. It's just like to activate a new PC....it doesn't matter if he did that once already. The way does not 'use up' a key or license when it's made from w7 OEM_SLP. I suppose he did an upgrade when it was still free upgrade-able....but as we know the upgrade still works.
Even Windows 10 Home is KMS capable, but you get a set period of 45 days instead of 180 (this works with emulated KMS servers only, real servers wouldn't activate).
Small correction: Real KMS servers in the wild wouldn't. But MS internal lab KMS servers do. I guess that's why all Editions are KMS-capable - to ease internal lab testing. Note: Hotbird64's utilities let you emulate an MS Internal Lab KMS server. Just use the correct ePID range (get from LicenseManager database). It, however, doesn't make any sense to do that, as no one outside MS Lab could possibly run such a server. Detectable as hell.
KMSpico, MTK & KMS_VL_ALL (both editions) are capable of activating Home for ages. 40 days for 8.x WMC and 45 for 8.x/10 Home, or the other way around.
Well, it's 180 days for all Windows 7, 8, 8.1 and 10 officially Volume-capable Editions. Then, it's 30 days for Windows 8.0 Retail. Finally, it is 45 days for Windows 8.1 Retail and Windows 10 Retail. The reason they increased it to 34 days is probably, that Windows 8.0 Retail entered Panic Mode immediately after KMS activation (as Windows always nags when the remaining activation time is 30 days or less). AFAIK, a remaining KMS activation time of 30 days or less also lead to increased/immediate, permanent reactivation attempts that put their KMS server in the Lab under load. So, they added a bit of grace.
Microsoft could just give away Win10 for free. But then people will cry about how MS tries to make money through data harvesting and apps. Another alternative is a Windows subscription but that would also upset people.
LOL. They did that officially nagging people to do the upgrade (gwx) GetWindowsX(10).... The servers behind it are still doing their job. And yes you still can get w10 upgrade for free and the way to is official....