Is Zakat or Sadaqat obligatory upon a person who is required to pay rent for government housing for two years after his service was extended under a clause that does not include housing, knowing that he does not possess money in the country where he works, but he owns real estate and agricultural land in his home country, and he has not been officially notified of vacating the housing or of the obligation to pay rent in advance?

Your friend is obligated to repay the amount to the government entity. The reason for the error and who bears its consequences must be considered according to the applicable regulations. If your friend is compelled to repay the amount and does not have sufficient funds, he is considered among the ghārimīn (those in debt) who are eligible for zakat. As for the properties and agricultural lands he owns, their value should be considered: if they are insufficient for his needs and his debt, he is permitted to receive zakat to cover both.