What is the ruling on preparing a feast and offering a gift to an official at work upon his transfer, taking into consideration the suspicion of bribery?

There is no harm in what the husband wishes to do, whether it is preparing a feast or buying a gift for the official. A gift is commendable and engenders affection, for the Prophet, peace and blessings be upon him, said: "Give gifts, and you will love one another." It is not considered a bribe because bribery is the giving of money to nullify a right, validate a falsehood, or attain something one does not deserve. This situation does not fall under that category, especially since the official will be transferred. As for the feast, it is preferable for the husband to prepare it himself and not impose on his colleagues. It is forbidden for him to force them to pay money.