No, it is not just for immediate family. That has never been the case. Disney's wording on the offer says nothing of the sort. All it says is "up to six tickets may be purchased during the offer period." We have used them for friends and extended family since the program began. The only specific language related to immediate families is the fact that you can buy more than 6 tickets IF you have more than 5 military dependents. So, a family of 7 or 8 could buy enough for all of them.
They also have never enforced the "one ticket has to be used by the active duty member" part of it. I am a dependent spouse and have gone some years where I went to WDW twice and took either my kids or friends, using up all six tickets, and every year at DL (where we have APs), we buy 4 tickets for my sister, her husband, and 2 kids, one for my best friend, and one for my MIL. We usually buy them at
Disneyland directly and have never had an issue.
OP: If the tickets are ordered from SoG VERY SOON, it will be fine. Like, have him call them TODAY. They have to send him an email with some forms attached, which he has to email back (he will need a scanner) and then they will call him for his credit card number. This process can take a few days, but once they get his payment, they FedEx the tickets so he will have them quickly. They do charge $10 for shipping. He can then mail out the tickets to individuals, or to one of you, to distribute to the group on day one.