Dear Mr. Danny,
I am writing to you because I want to take a four-day leave from the following Monday. My mother is sick, and she is in hospital, her illness is getting worse, so I have to go there to take care of my mother. I tried to finish my part early in our project. I talked to John, and he promised to help me handle the things that happened in my absence. I can assure you that I will check my email daily, I will answer and be ready for emergency phone calls from the office. If my mother recovers, I will try to come to the office earlier than usual and work on Sundays to catch up with anything I have missed.
I thank you very much for understanding my situation. I am grateful to you. I am looking forward to hearing from you soon.
Sincerely yours,
John Anderson