Is it permissible to complete a five-month scholarship after defending the thesis and being close to receiving the certificate, knowing that the granting institution reviews scholarships only annually or upon request for their termination, and is it permissible to take this money to meet needs before returning to the home country?

You may benefit from the full grant if its renewal is done in a sound manner, free from deception, falsification, or circumvention, especially given the mentioned need for the remainder of the grant to finalize transactions and return to your country. This is unless the regulations stipulate that the grant ends upon completion of studies. In that case, the excess money must be returned to the responsible authorities, or given as charity if it cannot be returned.