How can care be arranged?

I do not work, I am registered to take care of a disabled child, my daughter is 15 years old, I am disabled under PND. My mother is 85 years old, lives alone, was recently given group 1 visual disability, and the medical certificate states that she needs constant external assistance. If I understand correctly, I, her only daughter, cannot arrange care for myself, because I already have care for a disabled child. How can I take care of my grandmother for my son, her grandson, while being officially employed, without quitting my job? And does the postponement of the draft apply to him in such circumstances?