What is the religious ruling on an employee who submits a declaration to a banking institution stating that he is the sole guardian of his parents to obtain a medical guarantee, while his siblings also contribute to the parents' treatment? And what is the fate of this employee?

If the institution stipulates that the applicant for treatment must be the sole guarantor of the patient, then this condition must be met. Deception to obtain the service through a false application is considered fraud and forgery, both of which are reprehensible behaviors that Allah does not approve of, as Allah Almighty says: "And shun false statements" (Quran 22:30), and the Prophet, peace and blessings be upon him, said: "He who cheats is not of me." If you are the sole guarantor of your parents, then there is no blame upon you. However, if your siblings share in the guardianship, then your declaration would be forged and your oath false, and you must repent and withdraw the application. Whoever submits a false declaration deserves the punishment of Allah, and his affair is subject to His will.