Can a person who owes maintenance at the bailiff's apply to cancel the debt because of bankruptcy proceedings against him?

No! An undisputed  maintenance debt is a guaranteed debt in bankruptcy proceedings, and the person against whom it has been made cannot apply for its cancellation just because of the bankruptcy proceedings. If, however,  he has paid the alleged maintenance debt, he is entitled, like any debtor, to challenge it, at the Bailiff's office,and prove that he has paid it.