Sure, I will give you that wildly improbable. The only way I see it is Hitler has a complete mental break or is injured and basically gets carried by ultra loyalists out of Berlin.
This could be interesting. Suppose that, much earlier than in OTL, he tries to shoot himself and fails. His arm twitches and he miraculously survives. He experiences a near-death hallucination that, combined with the stress of work and his already drug-addled state, causes him to mentally break. Withdrawal symptoms from whatever the heck he was on in the following days makes it worse.
His party smuggles him out of Germany to live on as a symbol of the continuation of the Nazi party, but they have to keep him away from anyone not in the inner circle because, between his semi-healed scars and his unintelligible babbling and sobbing (wow, I'm enjoying wrecking Hitler too much
), the entire surviving party would collapse if they found out that the Führer had allowed himself to fall to such a state.
Due to the scars, disguises, and his increasingly disheveled appearance, allied checkpoints fail to identify him, partly due to the assumption among Allies and Nazis alike that he is still in his Führerbunker. His inner circle manages to get an emergency medical passport for him, sending him to Allied-occupied Italy. Knowing that the war is a hopeless cause, they instead plan to start and fund various neo-nazi groups around the world in the hope that the NSDAP can rise from the ashes in some other countries. They decide to send Hitler to Brazil in secret for safe keeping, then concentrate on fostering anti-Allied sentiment in Germany, Austria, Sweden, and other Germanic-speaking countries, with little success. Eventually, they turn to South American fascism.
Hitler regains his mental faculties on his way to Brazil, but is under constant supervision by his party members. Repeated pleas to allow him to die go unanswered; they need him as a symbol. They tell him about their plan to make South America their base from which the the third Reich can rise from the ashes. Hitler is crushed and humiliated.
Hitler gains a great deal of weight as his amphetamine-withdrawal-fueled appetite rears its ugly head. His Parkinson's gets worse, but he manages to make some voice recordings for future use. He dies in 1952, in a heavily guarded villa in Brazil, heavily overweight, his face scarred, having been bedridden for over a year due to late-stage Parkinson's, treated like a mental patient by his own party. Unable to hold a pen, he has dictated his memoirs, but gone is the fire and conviction that once marked his words. All that remains is a sad, pitiful, and increasingly mentally ill man.
Massively improbable, but pretty entertaining to think about.