Here are sample leave applications templates for mother /Father illness/sickness due to transplantation, surgery, operation, heart attack, sugar, blood pressure, cancer etc. You can modify the easy format as your requirement.

Leave Application for Visiting Sick Mother

To,

The Manager,
Nestle International.

Dear Sir,

With due respect, it is stated with much distress that my mother is going through organ transplantation. She is having renal transplantation on this Thursday. I have to visit her and check upon her condition. Also, I need to be evaluating the donor health record because there is always a chance of cancer or tumor to be transferred from donor to recipient. I have a lot of going on my back. With responsibility this big on my head, I need to be there to take charge and make sure that all procedure goes on accurately. I will be very thankful if you grant me leave for two days.

Yours Sincerely,

Lina Bhatu

Leave Application due to Mother Sickness

To,
Andy Wood
Human Resource Manager, Turk Plast Pvt Ltd.

Respected Sir,

It is humbly stated that I work in this organization in Management department as senior head. I have been an employee of this organization for 4 months. It is to request you that I require leave for three days to visit my sick mother. Sadly, she has been diagnosed with brain tumor and our all family is going through a very hard time. This grief has shook us in worst ways. My mother wants us to visit her as soon as possible. Please permit me for leave. I will get back to work as soon as my mother condition stabilizes. I shall be very thankful to you for this.

Yours Truly,

Robert

Mother Serious Leave Application

Respectfully, I want to inform you that I need leave for two days only. I have received a call from our family doctor that my mother is not doing well and her joints pain is tremendously increasing. She needs some more high dosage drugs and surgical procedures and doctors need me approval before going for any alternative. They have scheduled a next concern session on Thursday this week. I
hope you understand my circumstances and permit me leave as early as possible.
I shall be grateful. I have already dealt with my clients and they are completely fine with delay orders. Thanking you.

Yours Faithfully,
Andy Wood