While I can’t speak for Wilhelm, I can tell you about what the remains of the Russian imperial family did.

Two of Nicholas II’s sisters and their families survived along with their mother. The Dowager Empress Maria and Grand Duchess Xenia originally fled to England as Queen Alexandra was the Empress’ sister. There, they lived almost entirely on the generosity of the British royal family and whatever they could make from selling the few belongings they’d brought with them. Maria eventually went back to her native county of Denmark where her nephew, the king at the time, provided her with an allowance. She already owned a country house named Hvidøre where she lived until her death.

It was a similar story for Xenia who stayed on in England. She was given Frogmore Cottage as a grace and favour home. In 1920, she was allowed to take control of Nicholas’ estate in England, but this was only worth £500. When her mother died, she inherited and sold Hvidøre along with much of her mother’s jewels. With this, she bought Wilderness House near Hampton Court and lived there until her death.

Nicholas other sister Olga actually stayed in Russia for a little while. Her husband was considered a commoner by the new government and so she was too by association. They rented a small farm in the Caucasus and worked it for about a year before Olga began to feel unsafe and the family joined her mother in Denmark. They lived at Hvidøre with her until her death when Olga, with her portion of the sale, bought a farm in Ballerup. It’s a little uncertain as to whether she received an allowance from the Danish royal family, but it doesn’t seem likely. Her family worked the farm much as they had in the Caucasus, and Olga supplemented this by selling her paintings. She and her husband eventually sold the farm and moved to Canada. Olga died only a few years later, in a tiny flat above a beauty parlour which she shared with two friends.

Most aristocrats who didn’t have the benefit of allowances from other families simply lived on the dwindling income that selling their jewels brought them. Nicholas II’s niece Irina attempted to start a fashion house with her husband, but the business wasn’t very successful and was eventually forced to close. In their final years, they were living almost exclusively off the remnants of a lawsuit won by her husband against MGM.

So, in conclusion, exiled royalty was generally able to survive by living on the generosity of others and by selling their belongings. They had no real skills with which to make their own money—and often felt it was beneath their dignity to do so. And so they struggled on with scraps until their misery was over.

For Wilhelm II, although he abdicated the throne and therefore surrendered his rights to any official income from the state, he (and other members of the Hohenzollern family) retained substantial holdings both within and outside of Germany. In addition to this property, Wilhelm had large cash reserves, to which he retained access.

The Weimar government also allowed the former royal family to keep many items that were housed in erstwhile Royal palaces. 60 train cars of their possessions were removed from the Potsdam complex and sent to the Netherlands, including silver, artwork, and expensive porcelains.

The wealth of the Hohenzollern family has been in the news relatively recently. A New York Times article from last March details how the current head of the house has been in negotiations with several state governments in an attempt to recover property that was expropriated by the East German government in the wake of WW2. The distinction here of East German is important, because the Hohenzollerns never lost ownership of many properties held in West Germany, and indeed still own some of them today.