We can't tell because Satoshi can be a group. But there's always a possibility. A decade passed already and it's been too long yet we still have no idea about who Satoshi is. Maybe he's still alive and just watching us while having his own freedom. If he's actually dead, then there would be lesser possibility of knowing the real Satoshi...
I'm just curious if his family does actually know that he is Satoshi, the one who created bitcoin...
Even if it's a group of people, there must be the leader of this group that should be considered the Satoshi. I don't think it's a group, though. For one, this forum's Satoshi was lost likely one person. More importantly, why would Hal Finney be the first Bitcoin recipient? A group of people could run some tests between themselves.
Satoshi could be a woman, though, as far as I know. People keep saying "he", but it could be a "she".
Perhaps, we'll never know. And I think it's for the best.