I could see my Sole Survivor as a guy who hasn't checked-out, but is instead just in total denial about the reality of his situation and convinced it's gotta all be a dream. Figures those scientists probably did something to him when he was in that pod, just like all the experiments they ran in Anchorage while he was in the service. Cockroaches the size of schnauzers? Super mutants and ghouls? The whole city in ruins? Just what was in the stuff they had him breathing after they closed the lid? For all he knows, they're poking and prodding him while he's passed out.

That would probably hold right up until the first time he got a sucking chest wound from a raider's bullet. After the Stimpak/Med-X/adrenaline cocktail worked through his system, the stark reality of what he'd found himself in would hit him with full force. He's not tripping on some experimental chemical or part of some elaborate fantasy, he really was on ice for 2 centuries and is now standing in the decaying ruins of his home. But that also means that his son is out there, that he's the only one left to save him, and his wife would never forgive him if he quit. When he's completed his mission and his son is safe, only then can he sit down and finish losing what's left of his mind. And it certainly helps the immersion that I'm a deadpan snarker IRL.

Look on the bright side, at least you're not an Elder Scrolls protagonist, so you didn't start the story in a prison cell or on your way to a date with the headsman's axe.