Tengu Witch Favoured Class Alternative- add one spell to your familiar?

[Pyrobait]

So the favored class option reads: 'Add one spell from the witch spell list to the witch's familiar. This spell must be at least one level below the highest spell level she can cast. If the witch ever replaces her familiar, the new familiar knows these bonus spells.'

1.Does this mean my familiar can cast the spell or just add to the witch's available spells per day?
2. If the former, does casting it through the familiar take away from the witch's spells per day?
3. Slightly unrelated, but is there a limit to the hexes a witch can do in a day like spells?

[ohokwy]

1. You just add it too the Witch's available spells per day.

2. No longer applicable.

3. No, there isn't, unless the specific Hex says so.

[Blake's Tiger]

For the Witch (and related archetypes of other classes using the familiar in this way), the familiar is the spellbook (I.e. the source from which you prepare your own spells for the day).

[Chess Pwn]

replace spellbook in for familiar and it makes sense what it's saying.