Answer:
Dear Dean of Faculty and Supervisor,
I am writing this letter to inform you that I will be absent during the course of my dissertation writing. Unfortunately, I need to travel out of the country to attend to my mother's medical treatment. This is an unexpected circumstance that has arisen, and it requires my immediate attention.
As my supervisor, I understand the importance of keeping you informed about my progress and any potential delays. However, due to this unforeseen situation, I will not be able to meet the deadlines previously set for my dissertation writing. I apologize for any inconvenience this may cause, and I am committed to completing my dissertation as soon as I return.
I have been in touch with my departmental colleagues and have made arrangements to ensure that my work is covered in my absence. I will also be reachable via email in case of any urgent matters that may arise.
I understand the importance of being present during the dissertation writing process, and I regret that I will not be able to be physically present. However, I am committed to keeping up with my dissertation work and completing it to the best of my ability.
Thank you for your understanding and support during this difficult time.
Sincerely,
[Your Name]