>>725070327
Mostly likely, Toby is being inspired by Contact for the DS. Everything we know about Gaster and those shenanigans so far points to it being similar in nature to the Professor from that game.
The quick rundown is that a guy realizes he's in a game and abuses the plot of the game to escape reality itself during the credits. A copy of himself is left behind, but otherwise he spends the majority of the game communicating with the player through a device while the player controls a young lad named Terry through a DEVICE.
In this case, FRIEND is likely either other being similar to the player or another part of the DEVICE Gaster uses to keep track of us.