Brotherhood of Trust

It turns out there's a thirteenth use for dragon's blood... Dumbledore changes Severus Snape's role in the war from spy to protector after deatheaters are spotted in Surrey. To do this Severus must put himself in close proximity to Harry. What's closer than brotherhood? Deageing. No slash/no ships. Minor swearing. Possible violence in the future. Infrequent updates. Not beta'd.