Is he going to play any other online games? At all? If he does, he's going to have to pay the "gold" fee, or whatever its called.
If the only game he was going to play online was ESO, then he's probably right that he'd be paying for something he wasn't going to use much.
Personally, I see the subscription as a service; like paying for my internet every month. They are going to be adding content on a schedule and maintaining the game/servers/fixing problems/whatever. I'm paying for that, and as long as what they are doing is keeping me happy, I have no problems paying for it. If they don't, or there are major problems they don't fix, I'll unsubscribe.
The people who don't want to pay for the game and the service do have the option of not playing. No one is being forced to pay for or buy anything.