Is the husband obligated to pay zakat again now, or should he wait for the worker to return the money, or should he insist on not taking it from him, after he gave it to the worker with the intention of zakat and then the other workers and the worker himself disdained it and consider it a debt that he wants to repay?

The basic principle is that it is not obligatory to inform the recipient of Zakat that it is Zakat. However, if it is known from their situation that they would not accept it otherwise, then informing them becomes obligatory.

Since the man refused to accept it as Zakat and took it as a loan instead, it is not permissible to count the money he holds as part of the Zakat. Your husband's obligation for Zakat remains, and he must immediately disburse it to its rightful recipients.