It’s Canon Now: Familiars can perform a help action

Especially with regard to flanking, but it does put them at risk to attack. Flanking rules go like this:

When making a melee attack, you get a +2 flanking bonus if your opponent is threatened by another enemy character or creature on its opposite border or opposite corner.… Only a creature or character that threatens the defender can help an attacker get a flanking bonus.

But also familiars can use the aid another action:

In melee combat, you can help a friend attack or defend by distracting or interfering with an opponent. If you’re in position to make a melee attack on an opponent that is engaging a friend in melee combat, you can attempt to aid your friend as a standard action. You make an attack roll against AC 10. If you succeed, your friend gains either a +2 bonus on his next attack roll against that opponent or a +2 bonus to AC against that opponent’s next attack (your choice), as long as that attack comes before the beginning of your next turn. Multiple characters can aid the same friend, and similar bonuses stack.

You can also use this standard action to help a friend in other ways, such as when he is affected by a spell, or to assist another character’s skill check.

The aid another action ONLY applies, however, to the familiar’s master, whereas flanking applies to all qualified characters.