Harry and Ron had only one option. They appeared in the Hall of Archives in the Ministry and started rooting around for known Death Eaters to see if they came across anything useful. After hours of fruitless searching Harry came across the file of Severus Snape. He opened it, just as he had done for all the others - to confirm he was dead. He didn't see the point, he had watched him die, but he opened it just the same. Out of interest he looked down to see where he was buried and found something quite strange. "Hey, Ron! Come look at this." Ron stared in amazement and read aloud "Buried - N/A. Body never recovered." He looked at Harry and they both knew... Snape was out there somewhere.
No matter how many times they said it, they still found enormous pleasure in saying "He's not dead!" And every spare moment was spent talking about how the doe patronus must have been his and how it all fitted together now. They discussed how to find him, and whether or not he wanted to be found, but they eventually agreed to wait until the anniversary of his parents death to go to Godric's Hollow and wait for him. They apparated near his old house and wandered around for a bit. Harry recalled pleasantly about how last time he was here he almost got killed by a snake, and Ron quickly shushed him and pointed at a figure in black robes in the graveyard. It was dark, so it was difficult to tell, but they were sure it was him. They approached carefully, wands raised, and saw that the figure was laying a wreath on James and Lily's grave. Harry lit his wand and the figure turned abruptly and in the wandlight, Severus Snape's face broadened into a wide smile.
Back at Harry's home, with a nice cup of tea and biscuits, Snape told how he made the unbreakable vow to Lily that he would always protect her son from harm. He explained a deep, rare magic that put part of his life essence into Harry when he made the vow. It was this that stopped Voldemort that night, because Snape had the Dark Mark and part of him was inside Harry, Voldemort couldn't kill the Dark Mark, because in doing so he would be brought down in a state beyond life. After a sip of tea and a rejection of a biscuit, he explained that because he died to save Harry, when Harry used the Resurrection Stone to see his parents, he also released the part of Snape that lived inside of him. The life essence of Snape reunited with his ghostly form and brought him back from the dead. On that night he watched as Voldemort killed him and cried with pride at what Harry had done.
Up on the moorland the following morning, Harry asked if he would use his Death Eater connections to summon Amycus and Alecto Carrow, and with a wave of his wand a black stream of smoke flew from the tip and followed the wind... Barely a minute later, a loud crack sounded and the Carrows were cursed on all sides, but where quick enough to deflect them. Green light flew through the air and blew a tree to twigs. The duelists ducked and dived and cast curse after curse towards their attackers. Snape, Ron and Harry circled around them and deflected everything that was launched at them. The trio started to get the upper hand and eventually were able to disarm one and put a full body-bind curse on the other. They tied them up magically and then released the petrified brother. They then interrogated them as to why they insisted upon causing havoc still. Amycus simply replied with "We shall complete the Dark Lord's bidding. We shall return to a state of pure-blood rule and stand united over Muggle-kind! We have been returning family heirlooms to their right-full owners, even if their line has died out. We shall seize power! We shall complete the Dark Lord's bidding, even if some of us are traitors." He spat on the ground at Snape's feet and then refused to look at him again.
The Minister arrived that afternoon and said in his loud, clear voice: "Alecto and Amycus Carrow. You are hereby charged of High Treason and I request your immediate transportation to Azkaban, where you will spend the remainder of your lonely, miserable days."