they still have lots of money.
even in tokyo, you might still see a large estate with the 葵のご紋 (tokugawa family crest) on it. some are CEO's now, etc...
in the meiji era, the last shogun Tokugawa Yoshinobu was granted the new title of Prince. he basically lived a quiet life with his wife and a handful of concubines selected from 大奥 (the the shogun's harem in Edo Castle). but his family line, as well as the other branches still survive with considerable wealth.
Tokugawa Yoshihiro, who would have been the 20th daimyo of Owari worked in the service of emperor Hirohito during WWII. after the US nuked japan, the emperor recorded a surrender message for the radio. the day before the recording was to be broadcast, the military attempted to destroy the recordings. however, Yoshihiro stashed a copy in a secret place and it was saved.
the US military dismantled the imperial system during the occupation. titles like prince, duke, etc, were thrown out. but the families who were originally in these posts were old samurai families with proud traditions. the tokugawa were no different. the main branches still maintain the a male head of the family (this person would have attained daimyo status if the shogunate had not collapsed.)