Short answer. Yes, in effect. The Revised Penal Code has a separate justifying circumstance called defense of relatives, which covers acting to protect your spouse, ascendants, descendants, siblings, and certain other relatives. If its requisites are met, you incur no criminal liability - the same result as self-defense, under a distinct legal heading.
What the law says
Anyone who acts in defense of the person or rights of his spouse, ascendants, descendants, or legitimate, natural or adopted brothers or sisters, or of his relatives by affinity in the same degrees, and those by consanguinity within the fourth civil degree
Revised Penal Code, Article 11 — Justifying Circumstances: Self-Defence And Defence Of Others. Read the full provision →
Defense of relatives is its own justifying circumstance
Protecting a family member falls under a heading distinct from self-defense, though it works the same way. The Revised Penal Code lists justifying circumstances — situations where a person does not incur any criminal liability — and includes anyone who acts in defense of the person or rights of his spouse, ascendants, descendants, or legitimate, natural or adopted brothers or sisters, and relatives by affinity in the same degrees and by consanguinity within the fourth civil degree. So the law expressly allows you to defend a defined circle of relatives. If the requirements are satisfied, the act is justified and you are not criminally liable, exactly as with defense of your own person.
The requisites you must meet
Defense of relatives borrows the first two requisites of self-defense. There must be unlawful aggression — a real, actual or imminent attack on your relative, not a mere insult or a fear in your head — and there must be reasonable necessity of the means employed to prevent or repel it, meaning your response has to be reasonably proportionate to the danger. Unlawful aggression is the indispensable element; without a genuine attack on the family member, the defense collapses no matter how sincere your intentions. Reasonable necessity is judged against the situation as it confronted you, not with the calm of hindsight, but excessive or retaliatory force goes beyond what the law protects.
The provocation twist
Here defense of relatives differs from self-defense in a subtle but important way. In self-defense you must show a lack of sufficient provocation on your own part. In defense of relatives, the law addresses the case where the relative you protected was the one who provoked the fight: it adds the further requisite, in case the provocation was given by the person attacked, that the one making defense had no part therein. In other words, even if your relative started it, you can still be justified — so long as you yourself had no part in giving that provocation. This lets you come to a relative's aid without being tainted by their own misconduct, provided you were not complicit in it.
Why these cases are won on the facts
Because a successful defense means no criminal liability at all, courts scrutinise each requisite closely, and the person invoking it generally has to prove it. Everything turns on the concrete facts: whether there was a true unlawful aggression against your relative, whether the force you used was reasonably necessary, and, where relevant, whether you were free of any part in the provocation. Preserve whatever shows what actually happened — the sequence of events, injuries, witnesses, and the immediacy of the threat. If you or a relative face charges arising from protecting a family member, do not rely on the label alone; bring the full account to a lawyer as early as possible.