My friend (girl) is dating a fourteen year old boy? Is this weird?

Why should it be weird ?

From one standpoint, it probably will be weird. As an adult, 2 years isn't a big deal. As a teenager, 2 years means a lot. Friends will probably have issues with this. Other school mates will probably have something to say. Really though, if the 2 of them are OK with it and it's not causing any problems... then who cares.

I can't imagine what a 16 year old girl would see in a 14 year old boy, but I guess it would depend on if the 14 year old's parents are cool with it. I would imagine her friends think it's a bit strange.

Yes its weird because girls generally mature faster than boys, so it is unusual that an older girl would be interested in a younger boy. Or have anything in common with them. But as long as both parents are cool with it and she doesn't have sex with him, it not wrong, just unusual.